Standard Names¶
Coils And Control¶
current_from_passive_loop¶
Induced current flowing in a passive axisymmetric conductor loop.
Current induced in a passive axisymmetric conducting loop by time-varying magnetic flux. Passive loops are non-connected conductors (distinct from active coil circuits) that respond to changing magnetic fields through electromagnetic induction.
The induced current is governed by Faraday's law and the loop resistance:
where \(\psi\) is the poloidal magnetic flux threading the loop, \(R\) is the loop resistance, and \(I\) is the resulting current. The sign convention follows the right-hand rule: positive current flows counter-clockwise when viewed from above.
Passive loop currents provide stabilization against vertical displacement events and contribute to plasma position control. Time constants are determined by the loop inductance and resistance: \(\tau = L/R\). Important for MHD stability analysis, disruption mitigation, and understanding electromagnetic coupling between plasma and conducting structures.
Unit: A
Status: Draft
Tags: coils-and-control, measured, time-dependent
current_from_poloidal_field_coil¶
Electric current flowing through a poloidal field coil (per turn).
Electric current flowing through one turn of the poloidal field coil. The total magneto-motive force (MMF) is obtained by multiplying by the number of turns:
Sign convention: positive current flows from side 1 to side 2 inside the coil, corresponding to counter-clockwise direction when viewed from above (consistent with positive toroidal direction). This convention ensures consistency with right-hand rule for magnetic field direction.
The magnetic field produced by the coil at a point is calculated using the Biot-Savart law:
Typical PF coil currents range from 1 kA to 50 kA depending on machine size and coil function. Time-dependent measurements are used for equilibrium reconstruction, shape control, and plasma current evolution analysis.
Unit: A
Status: Draft
Tags: coils-and-control, measured, time-dependent
number_of_turns_of_passive_loop¶
Effective number of turns in passive loop element for magnetic field calculations.
Number of effective turns in the passive loop cross-section element used for calculating magnetic fields. This value includes the sign of the number of turns: positive indicates current flows counter-clockwise when viewed from above (positive toroidal direction), negative indicates clockwise flow. The sign convention follows the right-hand rule for current direction.
This parameter is essential for relating induced currents to magnetic field contributions via Ampère's law:
where \(N\) is the number of turns, \(I\) is the loop current, and \(r\) is the distance from the loop center. The effective turns account for the actual winding geometry and any series/parallel connections in the loop structure.
Used in MHD equilibrium reconstruction, passive stabilization analysis, and eddy current calculations for passive conducting structures.
Status: Draft
Tags: coils-and-control, calibrated, local-measurement
number_of_turns_of_poloidal_field_coil¶
Number of effective turns in a poloidal field coil element for calculating magnetic fields.
Number of effective turns in the poloidal field coil element, including the sign convention (positive for counter-clockwise current when viewed from above). This parameter is multiplied by the coil current to obtain the total magneto-motive force (MMF) producing the magnetic field:
where \(N\) is the number of turns and \(I\) is the current per turn. The effective turn count may differ from the physical number of windings due to series/parallel connections or partial coil segments. Sign convention: positive turns indicate current flowing counter-clockwise when viewed from above (positive toroidal direction). Used in equilibrium reconstruction and coil current calculations.
Status: Draft
Tags: coils-and-control, calibrated
position_of_poloidal_field_coil¶
Position vector of poloidal field coil geometric center in cylindrical coordinates.
Position vector \(\mathbf{r} = (R, Z, \phi)\) defining the spatial location of the poloidal field coil element's geometric center in cylindrical coordinates. The radial and vertical components (R, Z) specify the coil position in the poloidal plane, while the toroidal angle φ is typically zero for axisymmetric PF coil systems.
Components:
- radial_position_of_poloidal_field_coil: major radius R
- vertical_position_of_poloidal_field_coil: height Z
- toroidal_position_of_poloidal_field_coil: toroidal angle φ (usually 0 for axisymmetric coils)
Accurate coil positioning is essential for: 1. Equilibrium reconstruction (EFIT, LIUQE, etc.) 2. Plasma shape and position control 3. Electromagnetic force calculations 4. Coil-plasma mutual inductance modeling
Position uncertainties of ~1 cm can significantly impact reconstruction accuracy.
Unit: m
Status: Draft
Tags: coils-and-control, calibrated, cylindrical-coordinates
radial_position_of_poloidal_field_coil¶
Major radius (R coordinate) of poloidal field coil geometric center in cylindrical coordinates.
Radial coordinate (major radius R) of the poloidal field coil element geometric center in cylindrical coordinates (R, Z, φ). This defines the radial position of the rectangular or other cross-sectional coil geometry. Together with vertical_position_of_poloidal_field_coil and coil dimensions (width, height), this fully specifies the coil's spatial location for magnetic field calculations.
Coil positions are critical inputs for equilibrium reconstruction codes (e.g., EFIT) and for calculating plasma-coil electromagnetic coupling. Position accuracy directly affects reconstruction quality and control system performance. Typical PF coil radii range from 0.5 to 10 meters depending on machine size.
Unit: m
Status: Draft
Tags: coils-and-control, calibrated, cylindrical-coordinates
radial_width_of_poloidal_field_coil¶
Horizontal full width (radial extent) of poloidal field coil rectangular cross-section.
Horizontal full width of the poloidal field coil element's rectangular cross-section in the radial direction. This is the total radial extent of the coil conductor bundle, not the radius of individual turns.
The cross-sectional area is given by:
where \(w_{radial}\) is this radial width and \(h_{vertical}\) is the vertical height. This area, combined with the number of turns and current density, determines the total coil current capacity and thermal/mechanical constraints. Typical PF coil widths range from 0.05 to 0.5 meters. Used in electromagnetic force calculations and detailed coil modeling.
Unit: m
Status: Draft
Tags: coils-and-control, calibrated
vertical_height_of_poloidal_field_coil¶
Vertical full height of poloidal field coil rectangular cross-section.
Vertical full height of the poloidal field coil element's rectangular cross-section. This is the total vertical extent of the coil conductor bundle.
The cross-sectional area is given by:
where \(w_{radial}\) is the radial width and \(h_{vertical}\) is this vertical height. Larger cross-sections allow higher currents and better thermal performance but increase electromagnetic forces and structural loads. Typical PF coil heights range from 0.05 to 0.5 meters depending on coil function and machine size. This parameter is essential for accurate magnetic field modeling and structural analysis.
Unit: m
Status: Draft
Tags: coils-and-control, calibrated
vertical_position_of_poloidal_field_coil¶
Height (Z coordinate) of poloidal field coil geometric center in cylindrical coordinates.
Vertical coordinate (height Z) of the poloidal field coil element geometric center in cylindrical coordinates (R, Z, φ). This defines the vertical position of the rectangular or other cross-sectional coil geometry. Together with radial_position_of_poloidal_field_coil and coil dimensions (width, height), this fully specifies the coil's spatial location.
Vertical positioning is especially important for shaping coils and vertical stability control. PF coil heights typically span from below the divertor region to above the upper X-point, ranging from -3 to +3 meters (machine dependent). Position accuracy affects plasma shape control and equilibrium reconstruction fidelity.
Unit: m
Status: Draft
Tags: coils-and-control, calibrated, cylindrical-coordinates
Core Physics¶
effective_charge¶
Effective plasma charge number characterizing average ion charge state.
Effective charge number \(Z_{eff}\) defined as:
where the sum is over all ion species with density \(n_i\) and charge \(Z_i\), and \(n_e\) is the electron density.
\(Z_{eff}\) characterizes the average ion charge state and impurity content. Pure deuterium plasma has \(Z_{eff} = 1\), while impurities increase \(Z_{eff}\). Higher \(Z_{eff}\) increases plasma resistivity and bremsstrahlung radiation but can improve energy confinement. Typical values: 1.5-3.0.
Status: Draft
Tags: core-physics, derived, spatial-profile
electron_density¶
Total electron number density including thermal and non-thermal populations.
Electron number density \(n_e\) representing the total concentration of electrons per unit volume, including both thermal (Maxwellian) and non-thermal (e.g., runaway, beam-injected) populations.
Electron density is measured by interferometry, Thomson scattering, reflectometry, and other diagnostics. In tokamak core plasmas, typical values range from \(10^{19}\) to \(10^{21}\) m\(^{-3}\).
The electron density determines plasma collisionality, refractivity for electromagnetic waves, and appears in the plasma frequency:
Unit: m^-3
Status: Draft
Tags: core-physics, measured, spatial-profile
electron_pressure¶
Total electron pressure including thermal and non-thermal contributions.
Total electron pressure \(p_e\) including contributions from both thermal (Maxwellian) and non-thermal (fast, runaway) electron populations.
For an isotropic distribution, the pressure is related to the kinetic energy density. The total electron pressure contributes to the MHD force balance:
where \(p_i\) is the ion pressure and \(\mathbf{j}\) is the current density. Electron pressure gradients drive transport and affect MHD stability.
Unit: Pa
Status: Draft
Tags: core-physics, derived, spatial-profile
electron_temperature¶
Electron temperature in plasma.
Electron temperature \(T_e\) representing the average kinetic energy of electrons in the plasma. Related to the electron thermal velocity by:
where \(m_e\) is the electron mass.
Electron temperature is typically measured by Thomson scattering, electron cyclotron emission (ECE), or charge exchange spectroscopy. In tokamak core plasmas, \(T_e\) ranges from ~100 eV to 10+ keV. Temperature profiles are crucial for transport analysis, fusion reactivity calculations, and plasma confinement studies.
Unit: eV
Status: Draft
Tags: core-physics, measured, spatial-profile
fit_chi_squared_of_electron_temperature¶
Chi-squared goodness-of-fit metric for electron temperature profile fitting.
Chi-squared goodness-of-fit statistic for electron temperature profile fitting, defined as:
where \(w_i\) is the weight, \(T_{fit,i}\) is the reconstructed value, \(T_{meas,i}\) is the measured value, and \(\sigma_i\) is the measurement standard deviation.
A reduced chi-squared \(\chi^2_{red} = \sum_i \chi^2_i / N_{dof}\) near 1.0 indicates a good fit consistent with measurement uncertainties. Values much larger than 1 suggest systematic discrepancies or underestimated errors.
Status: Draft
Tags: core-physics, derived
fit_reconstructed_electron_temperature¶
Electron temperature value reconstructed from fitting procedure.
Electron temperature \(T_{e,fit}\) reconstructed from fitting measured values to a smooth functional form (e.g., polynomial, spline, or physics-based parametric model).
The reconstructed values are evaluated at the measurement locations to assess fit quality by comparison with the measured values. The difference between reconstructed and measured values, weighted by measurement uncertainty, gives the chi-squared metric.
For line-integrated measurements (e.g., ECE with significant chord averaging), the reconstructed value represents the line-integrated quantity rather than a local temperature.
Unit: eV
Status: Draft
Tags: core-physics, reconstructed, spatial-profile
fit_weight_of_electron_temperature_measurement¶
Statistical weight assigned to measured electron temperature values in profile fitting.
Weight \(w_i\) assigned to each measured electron temperature value in the fitting process used to construct smooth radial profiles from discrete measurements.
Weights are typically based on measurement uncertainty: \(w_i = 1/\sigma_i^2\) where \(\sigma_i\) is the standard deviation of measurement \(i\). Higher weights are given to more accurate measurements.
Used in least-squares minimization to obtain fitted profiles. The weighted chi-squared is:
Status: Draft
Tags: core-physics, derived, equilibrium-reconstruction
thermal_electron_density¶
Electron number density of thermal (Maxwellian) population only.
Thermal electron density \(n_{e,th}\) representing only the Maxwellian (thermalized) component of the electron population, excluding non-thermal populations such as runaway electrons or beam-injected fast electrons.
The thermal density satisfies \(n_{e,th} \leq n_e\) where \(n_e\) is the total electron density. In most tokamak plasmas, non-thermal populations are negligible and \(n_{e,th} \approx n_e\).
Thermal density is used in calculating thermal pressure \(p_{e,th} = n_{e,th} T_e\) and in transport analysis where non-thermal particles must be treated separately.
Unit: m^-3
Status: Draft
Tags: core-physics, derived, spatial-profile
thermal_electron_pressure¶
Thermal electron pressure from random thermal motion only.
Thermal electron pressure \(p_{e,th}\) associated with random thermal motion of the Maxwellian electron population, defined as:
where \(n_{e,th}\) is the thermal electron density and \(T_e\) is the electron temperature.
This quantity represents the pressure from thermal motion \(\sim \langle (v - \langle v \rangle)^2 \rangle\) and excludes directed motion and non-thermal populations. It is the primary contribution to electron pressure in most tokamak plasmas.
Unit: Pa
Status: Draft
Tags: core-physics, derived, spatial-profile
volume_averaged_effective_charge_due_to_ohmic¶
Volume-averaged effective charge estimated from ohmic flux consumption.
Volume-averaged effective charge \(\langle Z_{eff} \rangle_V\) estimated from the resistive flux consumption during the ohmic heating phase.
During ohmic-only operation, the loop voltage is related to plasma resistance, which depends on \(Z_{eff}\) through the Spitzer resistivity:
By measuring the loop voltage, plasma current, and electron temperature profile during ohmic phase, \(Z_{eff}\) can be inferred from the global resistive dissipation. This method provides a spatially-averaged value and is most reliable when other heating sources are minimal.
Status: Draft
Tags: core-physics, derived, global-quantity, ohmic-heating
Equilibrium¶
cross_sectional_area_of_flux_surface¶
Poloidal cross-sectional area enclosed by flux surface.
Poloidal cross-sectional area \(A(\rho)\) enclosed by a flux surface at radial position \(\rho\), calculated as the area bounded by the flux surface contour in the \((R,Z)\) poloidal plane.
For circular cross-sections, \(A = \pi a^2\) where \(a\) is the minor radius. For shaped plasmas, the area must be calculated by integrating over the actual flux surface boundary.
This quantity is used in calculating volume-averaged plasma parameters and appears in the relationship \(V = 2\pi R_{geom} A\) for toroidal geometry, where \(R_{geom}\) is the geometric center major radius.
Unit: m^2
Status: Draft
Tags: equilibrium, spatial-profile
cross_sectional_area_of_plasma_boundary¶
Cross-sectional area of plasma boundary in poloidal plane.
Poloidal cross-sectional area \(A\) of plasma boundary at last closed flux surface. Calculated as area enclosed by boundary contour in \((R,Z)\) plane. Related to volume by \(V = 2\pi R_{geom} A\) for circular cross-sections. Used in calculating averaged plasma density and shape factor calculations.
Unit: m^2
Status: Draft
Tags: equilibrium, global-quantity
elongation_of_plasma_boundary¶
Elongation of plasma boundary cross-section.
Elongation \(\kappa\) of the plasma boundary, measuring vertical stretching of the poloidal cross-section. Defined as ratio of vertical to horizontal extent. Full elongation: \(\kappa = (Z_{max} - Z_{min})/(R_{max} - R_{min})\). Higher elongation improves confinement but reduces MHD stability margins. Typical values: 1.0 (circular) to 2.0 (highly elongated).
Status: Draft
Tags: equilibrium, global-quantity
equilibrium_reconstruction_weight_of_faraday_rotation_angle_constraint¶
Weight assigned to Faraday angle measurement in reconstruction cost function.
Weight assigned to Faraday rotation angle measurement in equilibrium reconstruction algorithm. Controls relative influence of polarimetry diagnostic compared to other measurements (flux loops, magnetic probes) in determining final equilibrium solution.
Status: Draft
Tags: equilibrium, equilibrium-reconstruction
equilibrium_reconstruction_weight_of_flux_loop_constraint¶
Weight assigned to flux loop measurement in reconstruction cost function.
Weight assigned to flux loop measurement in equilibrium reconstruction algorithm. Controls relative importance of this flux loop compared to other diagnostics in minimizing reconstruction cost function \(J = \frac{1}{2} \sum_i w_i^2 (\Phi_{recon,i} - \Phi_{meas,i})^2 / \sigma_i^2\).
Status: Draft
Tags: equilibrium, equilibrium-reconstruction
equilibrium_reconstruction_weight_of_poloidal_magnetic_field_probe_constraint¶
Weight assigned to poloidal field probe measurement in reconstruction cost function.
Weight \(w_i\) assigned to poloidal magnetic field probe measurement in equilibrium reconstruction cost function. Reconstruction minimizes \(J = \frac{1}{2} \sum_i w_i^2 (B_{reconstructed,i} - B_{measured,i})^2 / \sigma_i^2\) where \(\sigma_i\) is measurement uncertainty. Higher weight increases influence of this diagnostic on final equilibrium solution.
Status: Draft
Tags: equilibrium, equilibrium-reconstruction
f_multiplied_by_poloidal_flux_derivative_of_f¶
Radial profile of F function multiplied by derivative of F with respect to poloidal flux.
Profile of \(F(\psi) F'(\psi)\) where \(F = R B_{tor}\) is poloidal current function and \(F' = dF/d\psi\). Appears in Grad-Shafranov equation source term representing toroidal field contribution. Related to toroidal plasma current and bootstrap current. Negative \(F F'\) corresponds to paramagnetic toroidal current.
Unit: T.m
Status: Draft
Tags: equilibrium, spatial-profile
flux_surface_area¶
Radial profile of flux surface area.
Flux surface area \(A(\rho)\) of each nested toroidal surface. Used in transport calculations and particle/energy balance. Related to volume: \(dV/d\rho = A(\rho)\). Larger area increases plasma-wall interaction. For circular flux surfaces: \(A \approx 2\pi R_0 (2\pi a)\). Shaping (elongation, triangularity) increases area.
Unit: m^2
Status: Draft
Tags: equilibrium, spatial-profile
flux_surface_area_derivative_with_respect_to_poloidal_flux¶
Derivative of flux surface cross-sectional area with respect to poloidal flux.
Radial derivative \(dA/d\psi\) of poloidal cross-sectional area with respect to poloidal flux. Used in transport equation formulations relating flux-based and geometric coordinates. Essential for source term calculations in transport modeling.
Unit: Wb^-1.m^2
Status: Draft
Tags: equilibrium, spatial-profile
flux_surface_area_derivative_with_respect_to_toroidal_flux_coordinate¶
Derivative of flux surface cross-sectional area with respect to toroidal flux coordinate.
Radial derivative \(dA/d\rho_{tor}\) of poloidal cross-sectional area. Used in transport codes for geometry factors in diffusion and convection terms. Related to volume derivative through flux surface geometry.
Unit: m
Status: Draft
Tags: equilibrium, spatial-profile
flux_surface_averaged_elongation¶
Radial profile of flux surface averaged elongation.
Flux surface averaged elongation \(\langle \kappa \rangle\) measuring vertical extent. Average of local elongation over flux surface. Related to vertical stability: high \(\kappa\) improves confinement but requires active control. Typical values: 1.5-2.0 in modern tokamaks. Affects beta limit and MHD stability.
Status: Draft
Tags: equilibrium, flux-surface-average, spatial-profile
flux_surface_averaged_inverse_major_radius¶
Flux surface average of inverse major radius.
Flux surface averaged \(\langle 1/R \rangle\). Geometric moment related to toroidal effects and 1/R weighting. Used in neoclassical theory for toroidal corrections and trapped particle physics. Appears in bootstrap current and rotation damping calculations.
Unit: m^-1
Status: Draft
Tags: equilibrium, cylindrical-coordinates, flux-surface-average, spatial-profile
flux_surface_averaged_inverse_squared_magnetic_field_strength¶
Flux surface average of inverse squared magnetic field strength.
Flux surface averaged \(\langle 1/B^2 \rangle\). Geometric moment appearing in neoclassical transport coefficients and bootstrap current calculations. Important for trapped particle fraction and banana orbit width. Used in Sauter bootstrap current formula.
Unit: T^-2
Status: Draft
Tags: equilibrium, flux-surface-average, spatial-profile
flux_surface_averaged_lower_triangularity¶
Radial profile of flux surface averaged lower triangularity.
Flux surface averaged lower triangularity \(\langle \delta_{lower} \rangle\) with respect to magnetic axis. Measures D-shape character of lower half of flux surfaces. Important for divertor configuration and vertical asymmetry characterization.
Status: Draft
Tags: equilibrium, flux-surface-average, spatial-profile
flux_surface_averaged_magnetic_field_strength¶
Flux surface averaged magnetic field strength (obsolescent).
Flux surface averaged magnetic field magnitude \(\langle B \rangle\). Note: This quantity is marked as obsolescent in IMAS Data Dictionary version 3.5.0. For neoclassical calculations, use geometric moments gm4 and gm5 instead. Historically used for field strength characterization.
Unit: T
Status: Draft
Tags: equilibrium, flux-surface-average, spatial-profile
flux_surface_averaged_major_radius¶
Radial profile of flux surface averaged major radius.
Flux surface averaged major radius \(\langle R \rangle\) weighted by inverse Jacobian. Defines effective geometric center of flux surface. Used in neoclassical transport calculations and trapped particle fraction. Shafranov shift increases \(\langle R \rangle\) with pressure. Related to toroidal current via force balance.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates, flux-surface-average, spatial-profile
flux_surface_averaged_parallel_adiabatic_electron_current_density¶
Radial profile of parallel adiabatic electron current density.
Flux surface averaged parallel current density from adiabatic electron response: \(j_{\parallel,e} = -n_e e (T_e/eB) abla_{\parallel} \ln p_e\). Pressure-gradient driven current arising from electron compressibility along field lines. Contributes to Pfirsch-Schlüter current in neoclassical theory. Small compared to Ohmic and bootstrap currents.
Unit: A.m^-2
Status: Draft
Tags: equilibrium, flux-surface-average, spatial-profile
flux_surface_averaged_parallel_bootstrap_current_density¶
Flux surface averaged parallel bootstrap current density.
Flux surface averaged bootstrap current density \(\langle j_{bs} \rangle\) driven by pressure gradient and trapped particles. Neoclassical self-generated current scaling as \(j_{bs} \propto \beta_{pol} abla p\). Can provide 50-80% of plasma current in advanced tokamak scenarios. Essential for steady-state operation.
Unit: A.m^-2
Status: Draft
Tags: equilibrium, flux-surface-average, spatial-profile
flux_surface_averaged_parallel_current_density¶
Flux surface averaged parallel plasma current density.
Flux surface averaged parallel current density \(\langle j_{\parallel} \rangle\) flowing along magnetic field lines. Sum of Ohmic, bootstrap, and beam/RF-driven currents. Related to safety factor: \(q = d\Phi_{tor}/d\psi\) and current profile shape affects stability. Peaked profiles with low edge current favor stability.
Unit: A.m^-2
Status: Draft
Tags: equilibrium, flux-surface-average, spatial-profile
flux_surface_averaged_parallel_diamagnetic_current_density¶
Radial profile of parallel diamagnetic current density.
Flux surface averaged parallel diamagnetic current density arising from pressure anisotropy and curvature drifts. Perpendicular pressure gradient drives \(\mathbf{j}_\perp = \mathbf{B} \times abla p / B^2\). Parallel projection contributes to equilibrium current balance. Related to Pfirsch-Schlüter current in toroidal geometry.
Unit: A.m^-2
Status: Draft
Tags: equilibrium, flux-surface-average, spatial-profile
flux_surface_averaged_parallel_ohmic_current_density¶
Radial profile of parallel Ohmic current density.
Flux surface averaged Ohmic current density \(\langle j_{Ohm} \rangle\) from resistive diffusion of toroidal electric field. Dominant current source in Ohmic plasmas: \(j_{Ohm} = \sigma E_{tor}\) where \(\sigma \propto T_e^{3/2}\). In auxiliary heated plasmas, supplemented by bootstrap and driven currents. Skin current during current ramp.
Unit: A.m^-2
Status: Draft
Tags: equilibrium, flux-surface-average, ohmic-heating, spatial-profile
flux_surface_averaged_squared_magnetic_field_strength¶
Flux surface average of squared magnetic field strength.
Flux surface averaged \(\langle B^2 \rangle\). Geometric moment used in MHD equilibrium analysis and pressure balance calculations. Related to magnetic energy density. Used for calculating magnetic pressure contributions.
Unit: T^2
Status: Draft
Tags: equilibrium, flux-surface-average, spatial-profile
flux_surface_averaged_squared_toroidal_flux_coordinate_gradient_magnitude¶
Flux surface average of squared gradient magnitude of toroidal flux coordinate.
Flux surface averaged geometric moment \(\langle | abla \rho_{tor}|^2 \rangle\). Metric coefficient characterizing flux surface geometry. Used in transport codes for calculating diffusion coefficients and coordinate transformations. Related to Jacobian and flux surface shape.
Status: Draft
Tags: equilibrium, flux-surface-average, spatial-profile
flux_surface_averaged_squared_toroidal_flux_coordinate_gradient_magnitude_divided_by_squared_magnetic_field_strength¶
Flux surface average of squared gradient magnitude divided by squared field strength.
Flux surface averaged geometric moment \(\langle | abla \rho_{tor}|^2 / B^2 \rangle\). Metric coefficient in drift kinetic and gyrokinetic theories. Appears in parallel transport calculations and field line curvature effects. Essential for neoclassical transport modeling.
Unit: T^-2
Status: Draft
Tags: equilibrium, flux-surface-average, spatial-profile
flux_surface_averaged_squared_toroidal_flux_coordinate_gradient_magnitude_divided_by_squared_major_radius¶
Flux surface average of squared gradient magnitude divided by squared major radius.
Flux surface averaged geometric moment \(\langle | abla \rho_{tor}|^2 / R^2 \rangle\). Metric coefficient used in neoclassical transport theory and gyrokinetic codes. Appears in drift kinetic equation and bounce-averaged transport coefficients. Essential for accurate neoclassical conductivity calculations.
Unit: m^-2
Status: Draft
Tags: equilibrium, flux-surface-average, spatial-profile
flux_surface_averaged_toroidal_current_density¶
Flux surface averaged toroidal plasma current density.
Flux surface averaged toroidal current density \(\langle j_{tor} \rangle\) in toroidal direction. Related to parallel current via pitch angle. Integration gives total toroidal current: \(I_p = \int \langle j_{tor} \rangle dA_{pol}\). Broadened by bootstrap current at edge in H-mode.
Unit: A.m^-2
Status: Draft
Tags: equilibrium, flux-surface-average, spatial-profile
flux_surface_averaged_toroidal_flux_coordinate_gradient_magnitude¶
Flux surface average of gradient magnitude of toroidal flux coordinate.
Flux surface averaged \(\langle | abla \rho_{tor}| \rangle\). Geometric moment characterizing radial variation of flux surfaces. Used in transport codes for metric tensor calculations and coordinate system definitions.
Status: Draft
Tags: equilibrium, flux-surface-average, spatial-profile
flux_surface_averaged_triangularity¶
Radial profile of flux surface averaged triangularity.
Flux surface averaged triangularity \(\langle \delta \rangle\) measuring horizontal asymmetry. Average of local triangularity over flux surface. Positive triangularity (D-shape) standard in tokamaks, improves H-mode access. Negative triangularity being explored for enhanced stability. Typical values: 0.2-0.5.
Status: Draft
Tags: equilibrium, flux-surface-average, spatial-profile
flux_surface_averaged_upper_triangularity¶
Radial profile of flux surface averaged upper triangularity.
Flux surface averaged upper triangularity \(\langle \delta_{upper} \rangle\) with respect to magnetic axis. Measures D-shape character of upper half of flux surfaces. Average over flux surface of local upper triangularity. Used for shape optimization and MHD stability analysis.
Status: Draft
Tags: equilibrium, flux-surface-average, spatial-profile
flux_surface_surface_area¶
Radial profile of toroidal surface area of flux surfaces.
Surface area \(S(\rho)\) of toroidal flux surface. For axisymmetric plasma: \(S = \oint dl_{pol} \cdot 2\pi R\) integrated around poloidal circumference. Used in particle balance and plasma-wall interaction calculations. Related to volume through \(dV/d\rho = S\) for certain coordinate choices.
Unit: m^2
Status: Draft
Tags: equilibrium, spatial-profile
flux_surface_volume¶
Radial profile of flux surface volume.
Volume \(V(\rho)\) enclosed within flux surface. Related to flux surface area: \(dV/d\rho = A(\rho)\). Used for calculating volume-averaged quantities and particle content. For circular cross-section: \(V \approx 2\pi^2 R_0 a^2\). Elongation and triangularity increase volume for given minor radius.
Unit: m^3
Status: Draft
Tags: equilibrium, spatial-profile
flux_surface_volume_derivative_with_respect_to_poloidal_flux¶
Derivative of flux surface volume with respect to poloidal flux.
Radial derivative \(dV/d\psi\) of volume enclosed by flux surface with respect to poloidal flux. Related to flux surface area through \(dV/d\psi = (dV/d\rho)(d\rho/d\psi)\). Used in transport equation formulations and particle balance calculations.
Unit: Wb^-1.m^3
Status: Draft
Tags: equilibrium, spatial-profile
flux_surface_volume_derivative_with_respect_to_toroidal_flux_coordinate¶
Derivative of flux surface volume with respect to toroidal flux coordinate.
Radial derivative \(dV/d\rho_{tor}\) of volume enclosed by flux surface. Equals flux surface area in toroidal flux coordinates. Used in transport codes for volume-integrated quantities and particle/energy balance equations.
Unit: m^2
Status: Draft
Tags: equilibrium, spatial-profile
geometric_minor_radius¶
Radial profile of geometric minor radius of flux surfaces.
Geometric minor radius \(a_{geo}(\rho) = (R_{outboard} - R_{inboard})/2\) measuring half-width of flux surface at midplane. Increases monotonically from 0 at axis to \(a\) at boundary. Used for normalized radial coordinate \(\rho = a_{geo}/a\) and profile parameterization. Differs from flux-based coordinates by geometry effects.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates, spatial-profile
internal_inductance¶
Internal inductance of plasma current distribution.
Normalized internal inductance \(l_i(3)\) characterizing plasma current profile peaking. Defined by integral of current density profile. Larger \(l_i\) indicates more peaked current (higher core current density). Affects MHD stability, confinement, and current diffusion timescales. Typical values: 0.5-1.5, with \(l_i \sim 0.8\) for steady-state profiles.
Status: Draft
Tags: equilibrium, global-quantity
lower_elongation_of_plasma_boundary¶
Lower half elongation of plasma boundary.
Elongation \(\kappa_{lower}\) of lower half of plasma boundary relative to geometric axis. Defined as \((Z_{axis} - Z_{min})/(R_{max} - R_{min})\) where \(Z_{axis}\) is the geometric axis height. Used to characterize vertical asymmetry in plasma shape, particularly in single-null diverted configurations.
Status: Draft
Tags: equilibrium, global-quantity
lower_triangularity_of_plasma_boundary¶
Lower triangularity of plasma boundary.
Lower triangularity \(\delta_{lower}\) characterizing D-shape of lower half of plasma boundary. Defined as horizontal displacement of lower midplane point from geometric axis normalized by minor radius. Important for divertor configuration and heat flux distribution in lower single-null plasmas.
Status: Draft
Tags: equilibrium, global-quantity
magnetic_field_line_length_for_single_poloidal_transit¶
Radial profile of magnetic field line length for single poloidal transit.
Connection length \(L_{conn}(\rho)\) for one complete poloidal circuit following magnetic field line. Increases with safety factor: \(L_{conn} \approx q \cdot 2\pi R_0\). Parallel transport timescale \(\tau_{\parallel} = L_{conn}^2 / (2 \chi_{\parallel})\). Important for impurity transport and parallel heat conduction. Edge connection length affects SOL physics.
Unit: m
Status: Draft
Tags: equilibrium, spatial-profile
magnetic_shear¶
Radial profile of magnetic shear.
Magnetic shear \(s = (r/q)(dq/dr)\) measuring rate of safety factor variation. Stabilizes drift waves and ballooning modes. High shear (\(|s| > 1\)) improves confinement but reduces bootstrap current. Reversed shear regions (\(s < 0\)) enable advanced scenarios with internal transport barriers.
Status: Draft
Tags: equilibrium, mhd-stability-analysis, spatial-profile
maximum_magnetic_field_strength_on_flux_surface¶
Maximum magnetic field strength on flux surface (obsolescent).
Maximum value of magnetic field magnitude \(B_{max}\) on each flux surface. Occurs at inboard midplane for standard tokamak due to \(1/R\) toroidal field variation. Note: Marked as obsolescent in IMAS DD v3.5.0. Used for trapped particle fraction and mirror ratio calculations.
Unit: T
Status: Draft
Tags: equilibrium, spatial-profile
minimum_magnetic_field_strength_on_flux_surface¶
Minimum magnetic field strength on flux surface (obsolescent).
Minimum value of magnetic field magnitude \(B_{min}\) on each flux surface. Occurs at outboard midplane for standard tokamak configuration. Note: Marked as obsolescent in IMAS DD v3.5.0. Defines magnetic well depth and trapped particle boundary.
Unit: T
Status: Draft
Tags: equilibrium, spatial-profile
minimum_safety_factor¶
Minimum value of safety factor.
Minimum value \(q_{min}\) of safety factor profile across all flux surfaces. Critical parameter for MHD stability analysis. For reversed shear profiles: \(q_{min}\) occurs inside plasma (not at axis). Rational surfaces where \(q = m/n\) are resonant for resistive modes. Location of \(q_{min}\) affects internal transport barriers.
Status: Draft
Tags: equilibrium, mhd-stability-analysis
minor_radius_of_plasma_boundary¶
Minor radius of plasma boundary.
Minor radius \(a\) of the plasma boundary, defined as half the radial extent: \(a = (R_{max} - R_{min})/2\) where \(R_{max}\) and \(R_{min}\) are the outermost and innermost major radius values of the boundary contour. Characteristic plasma size parameter used in normalized plasma parameters and scaling laws.
Unit: m
Status: Draft
Tags: equilibrium, global-quantity
normalized_poloidal_flux_at_plasma_boundary¶
Normalized poloidal flux value defining plasma boundary location.
Normalized poloidal flux \(\psi_{norm}\) at which the plasma boundary is defined. Normalization: \(\psi_{norm} = (\psi - \psi_{axis})/(\psi_{sep} - \psi_{axis})\). For fixed-boundary codes typically \(\psi_{norm} \approx 0.99\) (99.x% of separatrix value). For free-boundary codes equals 1.0 at true separatrix.
Status: Draft
Tags: equilibrium, flux-coordinates
normalized_poloidal_flux_coordinate¶
Normalized poloidal flux coordinate for radial position in flux coordinates.
Normalized poloidal flux coordinate \(\rho_{pol,norm}\) defined as:
where \(\psi\) is the poloidal magnetic flux, \(\psi_{axis}\) is the flux at the magnetic axis, and \(\psi_{LCFS}\) is the flux at the last closed flux surface (plasma boundary).
This coordinate varies from 0 at the magnetic axis to 1 at the plasma boundary. It provides an alternative radial coordinate to \(\rho_{tor,norm}\) and is particularly useful for equilibrium reconstruction and MHD analysis.
Status: Draft
Tags: equilibrium, flux-coordinates, spatial-profile
normalized_toroidal_beta¶
Normalized toroidal beta parameter.
Normalized toroidal beta \(\beta_N\) defined as \(\beta_N = 100 \beta_t a[m] B_0[T] / I_p[MA]\) where \(a\) is minor radius, \(B_0\) is toroidal field, and \(I_p\) is plasma current. Dimensionless measure of pressure relative to operational limits. Troyon limit: \(\beta_N < 4\) for MHD stability. Advanced tokamaks target \(\beta_N \sim 2-3\).
Status: Draft
Tags: equilibrium, global-quantity, performance-metric
normalized_toroidal_flux_coordinate¶
Radial profile of normalized toroidal flux coordinate.
Normalized toroidal flux coordinate \(\rho_{tor,norm}(\rho) = \sqrt{\Phi_{tor}/\Phi_{tor,boundary}}\). Standard radial coordinate for IMAS equilibrium profiles. Monotonically increasing from 0 (axis) to 1 (boundary). Used as independent variable for profiles_1d arrays. Approximately equal to normalized minor radius in circular plasmas.
Status: Draft
Tags: equilibrium, flux-coordinates, spatial-profile
normalized_toroidal_flux_coordinate_at_minimum_safety_factor¶
Normalized toroidal flux at minimum safety factor location.
Normalized toroidal flux coordinate \(\rho_{tor,norm}\) at the radial location where safety factor reaches its minimum value. For monotonic q-profiles: \(\rho_{q,min} = 0\) (at axis). For reversed shear: \(0 < \rho_{q,min} < 1\) indicating off-axis minimum. Used to characterize internal transport barrier location.
Status: Draft
Tags: equilibrium, flux-coordinates
plasma_pressure¶
Radial profile of plasma pressure.
Total plasma pressure \(p(\rho)\) including thermal electrons, ions, and fast particles: \(p = \sum_s n_s T_s + p_{fast}\). Key Grad-Shafranov input determining Shafranov shift and pressure-driven currents. Related to beta: \(\beta = 2\mu_0 \langle p \rangle / B_0^2\). Typical profiles: peaked on-axis with gradient scale length 0.2-0.4 m.
Unit: Pa
Status: Draft
Tags: equilibrium, spatial-profile
plasma_thermal_energy¶
Total thermal energy of confined plasma.
Total thermal energy \(W_{th}\) of plasma including electron and ion contributions: \(W_{th} = \frac{3}{2} \int (n_e T_e + \sum_i n_i T_i) dV\). Stored energy in plasma thermal pressure. Related to energy confinement time \(\tau_E = W_{th}/P_{input}\). For H-mode: typically 0.1-10 MJ depending on device size and heating power.
Unit: J
Status: Draft
Tags: equilibrium, global-quantity
plasma_volume¶
Total volume enclosed by plasma boundary.
Total plasma volume \(V\) enclosed by the plasma boundary surface. For axisymmetric toroidal plasma: \(V = \int 2\pi R \, dA\) integrated over poloidal cross-section area. Used in global energy balance, beta calculations, and fusion power scaling. Typical values: 10-1000 m³ depending on device size.
Unit: m^3
Status: Draft
Tags: equilibrium, global-quantity
poloidal_beta¶
Poloidal beta parameter for plasma pressure.
Poloidal beta \(\beta_p\) measuring ratio of plasma pressure to poloidal magnetic field pressure. Defined as \(\beta_p = \frac{4}{R_0 \mu_0 I_p^2} \int p \, dV\) where \(p\) is plasma pressure, \(I_p\) is plasma current, and \(R_0\) is major radius. Related to internal inductance and MHD equilibrium properties. Typical values: 0.5-2.0 in tokamaks.
Status: Draft
Tags: equilibrium, global-quantity
poloidal_circumference_of_plasma_boundary¶
Poloidal circumference of plasma boundary at outboard midplane.
Poloidal circumference \(L_{pol}\) of plasma boundary measured along field line at outer midplane. Arc length around poloidal contour of boundary: \(L_{pol} = \oint \sqrt{dR^2 + dZ^2}\). Related to connection length and parallel transport. Typical values: 10-30 m depending on elongation and device size.
Unit: m
Status: Draft
Tags: equilibrium, global-quantity
poloidal_component_of_magnetic_field_at_outboard_midplane¶
Radial profile of poloidal magnetic field strength at outboard midplane.
Poloidal magnetic field magnitude \(B_{pol}(\rho)\) at outboard midplane. Generated by toroidal plasma current: \(B_{pol} \propto I_p/a\). Decreases with minor radius outside current channel. Related to safety factor: \(q \propto B_{tor}/B_{pol}\). Low edge \(B_{pol}\) indicates high \(q_{edge}\) favorable for stability.
Unit: T
Status: Draft
Tags: equilibrium, spatial-profile
poloidal_flux_at_magnetic_axis¶
Poloidal flux at magnetic axis location.
Poloidal magnetic flux \(\psi_{axis}\) at the magnetic axis where poloidal field vanishes. Minimum value of poloidal flux function in confined region. Used to normalize flux coordinates: \(\psi_{norm} = (\psi - \psi_{axis})/(\psi_{boundary} - \psi_{axis})\). Essential reference value in Grad-Shafranov equilibrium solution.
Unit: Wb
Status: Draft
Tags: equilibrium, flux-coordinates
poloidal_flux_at_plasma_boundary¶
Poloidal magnetic flux at plasma boundary surface.
Poloidal magnetic flux \(\psi\) at the plasma boundary. For diverted plasmas, equals the separatrix flux \(\psi_{sep}\). For limited plasmas, equals flux at limiter contact point. Related to normalized flux by \(\psi_{norm} = (\psi - \psi_{axis})/(\psi_{boundary} - \psi_{axis})\). Fundamental quantity in Grad-Shafranov equilibrium solution.
Unit: Wb
Status: Draft
Tags: equilibrium, flux-coordinates
poloidal_flux_derivative_with_respect_to_toroidal_flux_coordinate¶
Radial derivative of poloidal flux with respect to toroidal flux coordinate.
Derivative \(d\psi/d\rho_{tor}\) relating poloidal flux to toroidal flux coordinate changes. Used in flux coordinate transformations and transport calculations. Related to safety factor through \(q = (d\Phi_{tor}/d\psi)(d\psi/d\rho_{tor})^{-1}(d\Phi_{tor}/d\rho_{tor})^{-1}\).
Unit: Wb.m^-1
Status: Draft
Tags: equilibrium, flux-coordinates, spatial-profile
poloidal_magnetic_flux¶
Poloidal magnetic flux enclosed by flux surface in tokamak.
Poloidal magnetic flux \(\psi\) enclosed by a toroidal flux surface, defined as:
where the integral is taken over any poloidal cross-section enclosed by the flux surface and \(\mathbf{B}_p\) is the poloidal magnetic field.
The poloidal flux labels flux surfaces in tokamak equilibria and is a fundamental quantity in MHD equilibrium calculations. It is related to the plasma current distribution through Ampère's law and determines the radial coordinate system in flux coordinates.
Unit: Wb
Status: Draft
Tags: equilibrium, flux-coordinates, spatial-profile
poloidal_magnetic_flux_at_magnetic_axis¶
Value of poloidal magnetic flux at the magnetic axis.
Poloidal magnetic flux \(\psi_{axis}\) at the magnetic axis (innermost flux surface where $ abla \psi = 0$).
This reference value is used to normalize the poloidal flux coordinate when the radial grid does not extend all the way to the magnetic axis. The normalized flux is then calculated as:
The difference \(\psi_{boundary} - \psi_{axis}\) represents the total poloidal flux swing between the axis and the plasma boundary.
Unit: Wb
Status: Draft
Tags: equilibrium, global-quantity
poloidal_magnetic_flux_at_plasma_boundary¶
Value of poloidal magnetic flux at the plasma boundary.
Poloidal magnetic flux \(\psi_{boundary}\) at the plasma boundary (last closed flux surface / separatrix).
This reference value defines the outer boundary of the confined plasma region and is used to normalize the poloidal flux coordinate:
For diverted plasmas, this corresponds to the flux at the X-point. For limited plasmas, it is the flux at the limiter contact point. The flux difference \(\psi_{boundary} - \psi_{axis}\) determines the total enclosed plasma current.
Unit: Wb
Status: Draft
Tags: equilibrium, global-quantity
poloidal_magnetic_flux_profile¶
Radial profile of poloidal magnetic flux.
Poloidal magnetic flux \(\psi(\rho)\) as function of flux surface coordinate. Fundamental solution of Grad-Shafranov equation: \(\Delta^* \psi = -\mu_0 R^2 p'(\psi) - F F'(\psi)\) where \(\Delta^*\) is elliptic operator. Used to define normalized flux coordinate \(\psi_{norm} = (\psi - \psi_{axis})/(\psi_{boundary} - \psi_{axis})\). Monotonically increasing from axis to boundary.
Unit: Wb
Status: Draft
Tags: equilibrium, flux-coordinates, spatial-profile
position_of_active_limiter_point¶
Position vector of active limiter contact point.
Two-dimensional position vector \((R, Z)\) of the active limiter point in cylindrical coordinates. Marks the tangency point between plasma boundary and limiter surface, defining the outer edge of confined plasma in limited configuration.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates
position_of_geometric_axis_of_plasma_boundary¶
Position of geometric center of plasma boundary.
Two-dimensional position vector \((R, Z)\) of the geometric axis of the plasma boundary in cylindrical coordinates. Geometric axis defined as midpoint of bounding box: \(R_{axis} = (R_{min} + R_{max})/2\) and \(Z_{axis} = (Z_{min} + Z_{max})/2\). Used as reference point for plasma shaping parameters (elongation, triangularity).
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates
position_of_magnetic_axis¶
Position vector of magnetic axis.
Two-dimensional position vector \((R, Z)\) of the magnetic axis in cylindrical coordinates. Defines the point where \(\mathbf{B}_{pol} = 0\) and flux surfaces are centered. Fundamental reference point for flux coordinate systems and plasma equilibrium characterization.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates
position_of_plasma_boundary_outline¶
Position vector contour defining plasma boundary shape.
Two-dimensional position vector \((R, Z)\) defining the closed contour of the plasma boundary in cylindrical coordinates. Array of position vectors forming the poloidal outline of the last closed flux surface. Used in equilibrium codes to define computational domain boundary or as constraint for free-boundary reconstruction.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates, spatial-profile
position_of_primary_strike_point¶
Position vector of primary strike point.
Two-dimensional position vector \((R, Z)\) of the primary strike point in cylindrical coordinates. Defines the location where the separatrix intersects the divertor target plate, establishing the boundary between private flux region and scrape-off layer. Essential for divertor design and heat flux analysis.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates
position_of_primary_x_point¶
Position vector of primary X-point.
Two-dimensional position vector \((R, Z)\) of the primary X-point in cylindrical coordinates. Marks the magnetic null where poloidal field vanishes (\(\mathbf{B}_{pol} = 0\)) and separatrix branches intersect. Fundamental topological feature defining diverted plasma configuration and divertor geometry.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates
radial_position_derivative_of_geometric_axis¶
Radial profile of radial derivative of geometric major radius.
Derivative \(dR_{geo}/d\rho\) of flux surface geometric center position. Measures Shafranov shift gradient driven by pressure and current profiles. Positive values indicate outward shift increasing with radius. Used in equilibrium solvers and coordinate transformations. Large gradients can affect transport and stability.
Status: Draft
Tags: equilibrium, spatial-profile
radial_position_of_active_limiter_point¶
Major radius of active limiter contact point.
Radial coordinate (major radius \(R\)) of the active limiter point where the plasma boundary contacts the limiter surface in limited configuration. This defines the radial extent of the confined plasma and the location of maximum plasma-wall interaction in limiter operation.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates
radial_position_of_geometric_axis¶
Radial profile of geometric major radius of flux surfaces.
Geometric major radius \(R_{geo}(\rho) = (R_{inboard} + R_{outboard})/2\) defining flux surface center. Increases with radius due to Shafranov shift from pressure and current. Used for approximate geometric calculations and profile mapping. Differs from flux surface averaged \(\langle R \rangle\) by \(O(\epsilon^2)\) corrections.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates, spatial-profile
radial_position_of_geometric_axis_of_plasma_boundary¶
Major radius of geometric center of plasma boundary.
Radial coordinate (major radius \(R\)) of the geometric axis of the plasma boundary, defined as \((R_{min} + R_{max})/2\) where \(R_{min}\) and \(R_{max}\) are the innermost and outermost radial positions of the boundary contour. Together with vertical position forms the geometric center for calculating elongation and triangularity shape parameters.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates
radial_position_of_inboard_point_at_outboard_midplane_height¶
Radial coordinate of inboard flux surface point at outboard midplane height.
Major radius \(R_{inboard}(\rho, Z=Z_{mag})\) of inboard intersection of flux surface with midplane. Defines inner limit of flux surface at magnetic axis height. Used for geometric profile construction and flux surface shape characterization. Shafranov shift moves inboard point outward with increasing pressure.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates, spatial-profile
radial_position_of_magnetic_axis¶
Major radius of magnetic axis location.
Radial coordinate (major radius \(R\)) of the magnetic axis where \(\mathbf{B}_{pol} = 0\) and \(|\mathbf{B}|\) is maximum. Innermost point of nested flux surfaces defining plasma geometric center. Shafranov shift moves magnetic axis outward from geometric axis due to finite pressure and current. Typical shift: 5-15 cm in medium-size tokamaks.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates
radial_position_of_outboard_point_at_midplane¶
Radial coordinate of outboard flux surface point at midplane.
Major radius \(R_{outboard}(\rho)\) of outboard midplane intersection of flux surface. Defines outer limit of flux surface at \(Z = Z_{mag}\). Minor radius \(a = (R_{outboard} - R_{inboard})/2\). Shafranov shift and elongation affect outboard position. Used for profile mapping and coordinate transformations.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates, spatial-profile
radial_position_of_plasma_boundary_outline¶
Major radius points defining plasma boundary contour.
Radial coordinate (major radius \(R\)) of points forming the plasma boundary outline in the poloidal cross-section. Array of \(R\) values paired with corresponding \(Z\) values forming closed contour. For fixed-boundary equilibrium codes, typically taken at \(\psi_{norm} \approx 0.99\) of separatrix value. For free-boundary codes, represents the separatrix (last closed flux surface) where \(\psi = \psi_{sep}\).
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates, spatial-profile
radial_position_of_primary_strike_point¶
Major radius of primary strike point location.
Radial coordinate (major radius \(R\)) of the primary strike point where the separatrix intersects the divertor target plate. Strike point is where field lines from the confined plasma first contact material surfaces. Location determines heat and particle flux distribution on divertor tiles. For double-null, primary strike point is at the more active X-point.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates
radial_position_of_primary_x_point¶
Major radius of primary X-point location.
Radial coordinate (major radius \(R\)) of the primary X-point in diverted plasma configuration. X-point is the magnetic null where poloidal field vanishes and separatrix branches intersect. For single-null, this is the only X-point. For double-null, primary X-point is typically the more active one (higher power flux). Critical for divertor physics and strike point locations.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates
radial_shafranov_shift¶
Radial profile of Shafranov radial shift of flux surfaces.
Shafranov shift \(\Delta(\rho) = R_{geo}(\rho) - R_{geo}(0)\) measuring outward displacement of flux surface centers. Driven by plasma pressure and toroidal current: \(\Delta \propto \beta_{pol} + l_i/2\). Positive (outward) shift increases with pressure. Affects aspect ratio and trapped particle fraction. Large shifts can limit achievable beta.
Unit: m
Status: Draft
Tags: equilibrium, spatial-profile
reference_major_radius_of_vacuum_toroidal_magnetic_field¶
Reference major radius where vacuum toroidal magnetic field is specified.
Reference major radius \(R_0\) at which the vacuum toroidal magnetic field \(B_0\) is specified. This is typically a fixed geometric location such as the middle of the vessel at the equatorial midplane.
The toroidal field varies as \(B_{tor}(R) \approx B_0 R_0 / R\) in vacuum (for large aspect ratio). The choice of reference radius \(R_0\) is a convention that must be consistent across all calculations using \(B_0\).
This parameter is used in defining the toroidal flux coordinate:
and in normalizing current densities.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates
safety_factor¶
Radial profile of safety factor.
Safety factor profile \(q(\rho) = (r/R_0)(B_{tor}/B_{pol})\) measuring field line winding. Ratio of toroidal to poloidal field line turns: after \(q\) toroidal transits, field line completes one poloidal turn. Monotonic \(q\) profiles stabilize MHD but limit performance. Reversed shear (\(dq/d\rho < 0\) in core) enables internal transport barriers.
Status: Draft
Tags: equilibrium, mhd-stability-analysis, spatial-profile
safety_factor_at_95_percent_flux_surface¶
Safety factor at 95% normalized flux surface.
Safety factor \(q_{95}\) at the flux surface containing 95% of the poloidal flux (\(\psi_{norm} = 0.95\)). Standard metric for edge safety factor and operational limits. Greenwald density limit and H-mode confinement scaling depend on \(q_{95}\). Typical range: 3-8. Lower values increase beta limit but reduce density limit.
Status: Draft
Tags: equilibrium, mhd-stability-analysis, performance-metric
safety_factor_at_magnetic_axis¶
Safety factor at magnetic axis.
Safety factor \(q_0\) at the magnetic axis where flux surfaces are centered. Minimum value of safety factor profile. For tokamaks with monotonic q-profile: \(q_0 < 1\) can trigger sawtooth oscillations via internal kink instability. Typical range: 0.7-1.2. Core MHD stability strongly dependent on \(q_0\) value.
Status: Draft
Tags: equilibrium, mhd-stability-analysis
surface_area_of_plasma_boundary¶
Surface area of toroidal plasma boundary.
Surface area \(S\) of the toroidal flux surface forming the plasma boundary. For axisymmetric plasma: \(S = \oint dl_{pol} \cdot 2\pi R\) where integral is around poloidal circumference. Related to plasma-wall interaction area and particle confinement time. Larger surface-to-volume ratio increases particle losses.
Unit: m^2
Status: Draft
Tags: equilibrium, global-quantity
toroidal_beta¶
Toroidal beta parameter for plasma pressure.
Toroidal beta \(\beta_t\) measuring ratio of plasma pressure to toroidal magnetic field pressure. Defined as \(\beta_t = \frac{2 \mu_0}{V B_0^2} \int p \, dV\) where \(B_0\) is vacuum toroidal field and \(V\) is plasma volume. Fundamental figure of merit for fusion performance. Typical values: 1-5% in conventional tokamaks, up to 10-15% in advanced scenarios.
Status: Draft
Tags: equilibrium, global-quantity
toroidal_component_of_magnetic_field_at_magnetic_axis¶
Toroidal magnetic field component at magnetic axis.
Toroidal magnetic field component \(B_{tor}\) at the magnetic axis location. Maximum value of toroidal field in plasma due to \(1/R\) dependence. Related to vacuum field by \(B_{tor}(R_{axis}) = B_0 R_0 / R_{axis}\) where \(R_0\) is reference radius. Used for calculating on-axis safety factor and plasma parameters.
Unit: T
Status: Draft
Tags: equilibrium
toroidal_flux¶
Radial profile of toroidal magnetic flux.
Toroidal magnetic flux \(\Phi_{tor}(\rho)\) enclosed within flux surface. Related to poloidal flux via safety factor: \(q = d\Phi_{tor}/d\psi\). Used to define toroidal flux coordinate \(\rho_{tor} = \sqrt{\Phi_{tor}/\pi B_0}\). Monotonically increasing from axis to boundary with \(\Phi_{tor,axis} = 0\).
Unit: Wb
Status: Draft
Tags: equilibrium, flux-coordinates, spatial-profile
toroidal_flux_coordinate¶
Radial profile of toroidal flux coordinate.
Toroidal flux coordinate \(\rho_{tor} = \sqrt{\Phi_{tor}/(\pi B_0)}\) where \(\Phi_{tor}\) is toroidal flux and \(B_0\) is vacuum toroidal field at reference position. Dimensional radial coordinate in meters. Related to normalized coordinate: \(\rho_{tor,norm} = \rho_{tor}/\rho_{tor,boundary}\). Used in transport codes and profile fitting.
Unit: m
Status: Draft
Tags: equilibrium, flux-coordinates, spatial-profile
toroidal_flux_derivative¶
Radial profile of radial derivative of toroidal flux.
Radial gradient \(d\Phi_{tor}/d\rho\) of toroidal flux. Related to flux surface area and magnetic field through flux conservation. Used in transport calculations for flux gradient terms. Determines relationship between flux coordinates and geometric coordinates. Essential for coordinate system transformations.
Unit: Wb
Status: Draft
Tags: equilibrium, flux-coordinates, spatial-profile
toroidal_flux_derivative_with_respect_to_poloidal_flux¶
Radial profile of toroidal flux derivative with respect to poloidal flux.
Derivative \(d\Phi_{tor}/d\psi\) relating toroidal and poloidal flux increments. Equals safety factor \(q\) by definition. Used in flux coordinate transformations and equilibrium solvers. Monotonically increasing for standard tokamak profiles. Jump discontinuities indicate rational surfaces with magnetic islands.
Status: Draft
Tags: equilibrium, flux-coordinates, spatial-profile
trapped_particle_fraction¶
Radial profile of trapped particle fraction.
Fraction \(f_{trap}(\rho)\) of particles trapped in magnetic wells due to toroidicity. Depends on inverse aspect ratio: \(f_{trap} \approx 1.46 \sqrt{\epsilon}\) for circular cross-section. Trapped particles cannot carry current, reducing conductivity. Bootstrap current proportional to \(f_{trap}\). Larger at outer radii where \(\epsilon\) increases.
Status: Draft
Tags: equilibrium, spatial-profile
triangularity_of_plasma_boundary¶
Triangularity of plasma boundary cross-section.
Triangularity \(\delta\) of the plasma boundary, measuring D-shape character of poloidal cross-section. Defined as horizontal displacement of midplane point relative to geometric axis, normalized by minor radius. Positive triangularity shifts plasma toward D-shape (more peaked on inboard side). Typical values: 0.2-0.5 for conventional tokamaks, negative for negative triangularity experiments.
Status: Draft
Tags: equilibrium, global-quantity
upper_elongation_of_plasma_boundary¶
Upper half elongation of plasma boundary.
Elongation \(\kappa_{upper}\) of upper half of plasma boundary relative to geometric axis. Defined as \((Z_{max} - Z_{axis})/(R_{max} - R_{min})\) where \(Z_{axis}\) is the geometric axis height. Asymmetry between upper and lower elongation indicates vertical asymmetry in plasma shape.
Status: Draft
Tags: equilibrium, global-quantity
upper_triangularity_of_plasma_boundary¶
Upper triangularity of plasma boundary.
Upper triangularity \(\delta_{upper}\) characterizing D-shape of upper half of plasma boundary. Defined as horizontal displacement of upper midplane point from geometric axis normalized by minor radius. Used to characterize shape asymmetry and MHD stability properties in double-null configurations.
Status: Draft
Tags: equilibrium, global-quantity
vacuum_toroidal_magnetic_field_at_reference_major_radius¶
Vacuum toroidal magnetic field magnitude at reference major radius.
Vacuum toroidal magnetic field \(B_0\) at the reference major radius \(R_0\). This is the toroidal field that would exist in the absence of plasma.
Sign convention: Positive \(B_0\) corresponds to counter-clockwise toroidal field direction when viewed from above the tokamak.
The product \(R_0 B_0\) is approximately conserved along toroidal field lines in vacuum:
This quantity must be consistent with the toroidal field coil current and the field mapping in the TF coil system. Typical values: 1-10 T for tokamaks.
Unit: T
Status: Draft
Tags: equilibrium, time-dependent
vertical_position_of_active_limiter_point¶
Height of active limiter contact point.
Vertical coordinate (height \(Z\)) of the active limiter point. Together with radial position defines the \((R, Z)\) location where plasma boundary touches the limiter, establishing the outermost confined flux surface in limited operation.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates
vertical_position_of_geometric_axis_of_plasma_boundary¶
Height of geometric center of plasma boundary.
Vertical coordinate (height \(Z\)) of the geometric axis of the plasma boundary, defined as \((Z_{min} + Z_{max})/2\) where \(Z_{min}\) and \(Z_{max}\) are the lowest and highest vertical positions of the boundary contour. Together with radial position forms the reference point for plasma shape characterization.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates
vertical_position_of_magnetic_axis¶
Height of magnetic axis location.
Vertical coordinate (height \(Z\)) of the magnetic axis. For up-down symmetric plasmas, magnetic axis typically near midplane (\(Z \approx 0\)). Vertical asymmetry in shaping or current profile causes vertical displacement. Used for plasma vertical position control and equilibrium reconstruction.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates
vertical_position_of_plasma_boundary_outline¶
Height coordinates defining plasma boundary contour.
Vertical coordinate (height \(Z\)) of points forming the plasma boundary outline in the poloidal cross-section. Array of \(Z\) values paired with corresponding \(R\) values forming closed contour. Together define the \((R,Z)\) boundary used for equilibrium reconstruction and shape analysis.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates, spatial-profile
vertical_position_of_primary_strike_point¶
Height of primary strike point location.
Vertical coordinate (height \(Z\)) of the primary strike point. Together with radial position defines the \((R, Z)\) location where separatrix contacts divertor target. Critical for calculating strike point angle, connection length, and divertor heat flux footprint width.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates
vertical_position_of_primary_x_point¶
Height of primary X-point location.
Vertical coordinate (height \(Z\)) of the primary X-point. Together with radial position defines the \((R, Z)\) location where the separatrix branches meet and \(\mathbf{B}_{pol} = 0\). X-point height determines strike point angles and divertor closure. Typical locations: below midplane for lower single-null, symmetric about midplane for double-null.
Unit: m
Status: Draft
Tags: equilibrium, cylindrical-coordinates
volume_enclosed_by_flux_surface¶
Volume enclosed inside a toroidal magnetic flux surface.
Volume \(V(\rho)\) enclosed by a toroidal magnetic flux surface at radial position \(\rho\). For axisymmetric toroidal geometry:
where the integral is over the poloidal cross-sectional area up to the flux surface.
This quantity is essential for volume-averaged quantities, particle inventory calculations, and transport analysis. The derivative \(dV/d\rho\) relates to the flux surface area and appears in transport equations.
Unit: m^3
Status: Draft
Tags: equilibrium, spatial-profile
Fueling¶
gas_flow_rate_from_gas_injection_valve¶
Gas flow rate measured at the exit of a gas injection valve.
Gas flow rate at the exit of a gas injection valve, measured in pressure-volume per unit time (Pa⋅m³⋅s⁻¹). This unit represents the product of pressure and volumetric flow rate, commonly used for gas injection systems in fusion devices.
The measurement characterizes the instantaneous gas delivery rate from valve systems connecting gas bottles to injection pipes. Flow rate is time-dependent and controlled by valve actuation. Typical applications include fueling, puffing for density control, and disruption mitigation gas injection.
The unit Pa⋅m³⋅s⁻¹ = N⋅m⁻²⋅m³⋅s⁻¹ = N⋅m⋅s⁻¹ = J⋅s⁻¹ = W, equivalent to power. This reflects the work rate of gas injection against plasma pressure. Conversion to particle flux requires temperature: \(\Gamma = \frac{Q}{k_B T}\) where Q is this flow rate, T is gas temperature, and \(k_B\) is Boltzmann constant.
Unit: Pa.m^3.s^-1
Status: Draft
Tags: fueling, local-measurement, measured, time-dependent
Fundamental¶
plasma_current¶
Total toroidal plasma current.
Total toroidal current \(I_p\) flowing in the plasma, defined as the surface integral of toroidal current density:
integrated over a poloidal cross-section.
Sign convention: Positive current is anti-clockwise when viewed from above (in the direction of increasing toroidal angle \(\phi\)).
The plasma current is a fundamental parameter controlling plasma confinement, MHD stability, and current-driven effects. It is related to poloidal flux and magnetic field via Ampère's law. Measurements typically use Rogowski coils or are inferred from magnetic equilibrium reconstruction.
Typical values: 0.1-15 MA in tokamaks depending on device size. Evolution of \(I_p\) determines resistive skin time, current diffusion, and operational scenarios.
Unit: A
Status: Draft
Tags: fundamental, global-quantity, measured, time-dependent
time¶
Time coordinate for time-dependent measurements.
Time coordinate \(t\) for time-dependent measurements and evolution of plasma quantities. Typically measured relative to a discharge reference time (e.g., \(t=0\) at plasma initiation or start of main heating phase).
Time resolution and sampling rates vary by diagnostic and measurement type. High-speed magnetics: 0.1-1 MHz, equilibrium reconstruction: 1-10 kHz, slow diagnostics: 10-100 Hz.
Accurate time synchronization across all diagnostics is essential for integrated data analysis and cross-validation of measurements.
Unit: s
Status: Draft
Tags: fundamental, time-dependent
Ic Heating¶
capacitance_of_ion_cyclotron_heating_antenna_matching_element¶
Capacitance value of impedance matching element in ion cyclotron heating system.
Capacitance of a tunable matching element used to optimize impedance matching between the transmission line and the antenna. Matching networks typically use vacuum variable capacitors that can be adjusted during operation to minimize reflected power. Capacitance values typically range from hundreds of pF to several nF.
Unit: F
Status: Draft
Tags: ic-heating, calibrated, time-dependent
current_amplitude_from_ion_cyclotron_heating_antenna¶
Amplitude of current signal measured at ion cyclotron heating antenna module.
Amplitude of the RF current signal measured at the antenna module. Current distribution across antenna straps determines the launched wave spectrum. High currents (hundreds to thousands of amperes) can cause ohmic heating in antenna components and structural stresses.
Unit: A
Status: Draft
Tags: ic-heating, measured, raw-data, time-dependent
distance_to_conductor_from_antenna_strap¶
Distance from antenna strap to conducting wall or conductor behind the strap.
Distance between the antenna strap and the conducting structure (wall or Faraday shield) behind it. This distance affects the antenna inductance and coupling impedance. Typical values range from a few cm to tens of cm. Used in electromagnetic modeling of antenna properties.
Unit: m
Status: Draft
Tags: ic-heating, calibrated
forward_power_from_ion_cyclotron_heating_antenna¶
Forward RF power arriving at the back of an ion cyclotron heating antenna module.
Forward radio frequency power measured at the back of an individual antenna module, before entering the plasma-facing structures. This measurement is typically obtained from directional couplers in the transmission line. The difference between forward and reflected power gives the net power delivered to the plasma.
Unit: W
Status: Draft
Tags: ic-heating, measured, raw-data, time-dependent
frequency_of_ion_cyclotron_heating_antenna¶
Operating frequency of ion cyclotron heating antenna system.
Radio frequency at which the ion cyclotron heating antenna operates, typically in the range of 25-100 MHz for tokamak plasmas. The frequency is tuned to match ion cyclotron resonance conditions for efficient heating and current drive. This is the average frequency across all modules of the antenna system.
Unit: Hz
Status: Draft
Tags: ic-heating, measured, time-dependent
phase_of_current_from_antenna_strap¶
Phase angle of current flowing through individual antenna strap.
Phase of the RF current in an individual antenna strap. Multiple straps in an antenna module are typically fed with controlled phase relationships to optimize the launched wave spectrum. The phase distribution determines the poloidal and toroidal mode numbers of the excited waves, controlling wave propagation direction and plasma heating location.
Unit: rad
Status: Draft
Tags: ic-heating, measured, time-dependent
phase_of_forward_power_from_ion_cyclotron_heating_antenna¶
Phase angle of forward RF power relative to first module in antenna array.
Phase of the forward power signal measured at an antenna module, referenced to the first module in the array. Phase differences between modules determine the toroidal mode number \(n_{\phi}\) of the launched wave spectrum and control the direction of wave propagation. Typical phasing schemes: monopole (0°), dipole (180°), or traveling wave (90°/270°).
Unit: rad
Status: Draft
Tags: ic-heating, measured, time-dependent
phase_of_reflected_power_from_ion_cyclotron_heating_antenna¶
Phase angle of reflected RF power relative to forward power of the same module.
Phase of the reflected power signal relative to the forward power at the same antenna module. This phase information, combined with power measurements, allows calculation of complex impedance and standing wave ratio in the transmission line. Used for antenna matching network optimization.
Unit: rad
Status: Draft
Tags: ic-heating, measured, time-dependent
position_of_antenna_strap_outline¶
Position vector defining antenna strap outline geometry in cylindrical coordinates.
Three-dimensional position vector (R, φ, Z) defining the outline contour of an ion cyclotron heating antenna strap. The outline consists of multiple position points that trace the strap geometry. This information is used for electromagnetic modeling, plasma-antenna coupling calculations, and visualization of antenna placement relative to plasma.
Unit: m
Status: Draft
Tags: ic-heating, calibrated, cylindrical-coordinates
power_launched_from_ion_cyclotron_heating_antenna¶
Total RF power launched into the vacuum vessel from ion cyclotron heating antenna.
Total radio frequency power launched from the ion cyclotron heating antenna system into the vacuum vessel. This represents the net power entering the plasma after transmission line losses but before plasma absorption. Calculated as the sum of power from all antenna modules minus reflected power. Used for energy balance calculations and heating efficiency analysis.
Unit: W
Status: Draft
Tags: ic-heating, heating-deposition, measured, time-dependent
pressure_amplitude_from_ion_cyclotron_heating_antenna¶
Amplitude of pressure measurement at ion cyclotron heating antenna module.
Pressure measured near the antenna module, typically in the transmission line or matching network. Pressure variations can indicate vacuum leaks, gas puffing effects, or plasma-antenna interactions. Monitoring pressure is important for preventing arcing and maintaining operational reliability.
Unit: Pa
Status: Draft
Tags: ic-heating, measured, time-dependent
radial_position_of_antenna_strap_outline¶
Major radius (R coordinate) of antenna strap outline points in cylindrical coordinates.
Radial coordinate (major radius R) defining the outline geometry of an ion cyclotron heating antenna strap. Multiple R, Z, φ points define the complete strap outline contour. This geometric information is essential for wave coupling calculations, plasma-antenna interaction modeling, and electromagnetic field simulations.
Unit: m
Status: Draft
Tags: ic-heating, calibrated, cylindrical-coordinates
reflected_power_from_ion_cyclotron_heating_antenna¶
Reflected RF power from an ion cyclotron heating antenna module.
Radio frequency power reflected back from the antenna module due to impedance mismatch between the antenna and plasma. High reflected power indicates poor coupling conditions and can damage transmission line components. Typical reflection coefficients range from 5-30% depending on plasma conditions and antenna tuning.
Unit: W
Status: Draft
Tags: ic-heating, measured, raw-data, time-dependent
toroidal_angle_of_antenna_strap_outline¶
Toroidal angle (φ coordinate) of antenna strap outline points in cylindrical coordinates.
Toroidal angle coordinate defining the outline geometry of an ion cyclotron heating antenna strap. The angle is measured counter-clockwise when viewing from above. Combined with R and Z coordinates, this defines the complete three-dimensional strap geometry.
Unit: rad
Status: Draft
Tags: ic-heating, calibrated, cylindrical-coordinates
toroidal_width_of_antenna_strap¶
Width of antenna strap in the toroidal direction.
Toroidal extent of the antenna strap conductor. Wider straps provide better coupling but may have different spectral properties. This parameter affects the toroidal wave number spectrum of the launched RF power. Note: This field is marked obsolescent in IMAS Data Dictionary version 3.42.0.
Unit: m
Status: Draft
Tags: ic-heating, calibrated
vertical_position_of_antenna_strap_outline¶
Height (Z coordinate) of antenna strap outline points in cylindrical coordinates.
Vertical coordinate (Z) defining the outline geometry of an ion cyclotron heating antenna strap. Multiple points define the poloidal extent of the strap. Strap positioning relative to the plasma affects coupling efficiency and power deposition profiles.
Unit: m
Status: Draft
Tags: ic-heating, calibrated, cylindrical-coordinates
voltage_amplitude_from_ion_cyclotron_heating_antenna¶
Amplitude of voltage signal measured at ion cyclotron heating antenna module.
Amplitude of the RF voltage signal measured at the antenna module. Voltage measurements, combined with current measurements, provide information about antenna impedance and coupling efficiency. High voltages (tens of kV) can lead to voltage breakdown and arcing, limiting operational capability.
Unit: V
Status: Draft
Tags: ic-heating, measured, raw-data, time-dependent
voltage_phase_from_ion_cyclotron_heating_antenna¶
Phase angle of voltage signal measured at ion cyclotron heating antenna module.
Phase of the RF voltage signal at the antenna module. Phase relationship between voltage and current determines the reactive and resistive components of antenna impedance. Used for impedance matching analysis and antenna tuning optimization.
Unit: rad
Status: Draft
Tags: ic-heating, measured, time-dependent
Interferometry¶
electron_count¶
Total number of electrons in the plasma volume.
Total number of electrons in the plasma, estimated from interferometer line-integrated density measurements. Calculated by integrating the reconstructed electron density over the plasma volume:
Typically obtained by combining multiple interferometer chords through tomographic inversion to reconstruct \(n_e(\mathbf{r})\), followed by volumetric integration. For tokamak plasmas, typical values range from \(10^{19}\) to \(10^{21}\) electrons depending on machine size and density. This quantity is useful for particle balance studies, fueling efficiency analysis, and integrated modeling validation. Uncertainty depends on spatial coverage and inversion accuracy.
Status: Draft
Tags: interferometry, derived, global-quantity, particle-balance, time-dependent
electron_line_averaged_density_from_interferometer_beam¶
Line-averaged electron density obtained by dividing line integral by path length.
Line-averaged electron number density obtained by dividing the line-integrated density by the geometric path length:
where \(L\) is the total path length along the line of sight. For reflected beams, \(L\) includes both forward and return paths. This quantity provides a simple density estimate representative of the plasma along the measurement chord. Typical tokamak values: \(10^{18}\) - \(10^{20}\) m⁻³. Note that this is a chord-averaged quantity; central density is typically higher than line-averaged values due to peaked density profiles.
Unit: m^-3
Status: Draft
Tags: interferometry, calibrated, line-integrated, measured, time-dependent
electron_line_integrated_density_from_interferometer_beam¶
Line-integrated electron density measured by interferometer along beam path.
Line-integrated electron number density measured along the interferometer beam path, defined as:
where the integral is taken along the line of sight and \(n_e(\mathbf{r})\) is the local electron density. Obtained from the measured phase shift using the conversion factor. For reflected beams (retroreflector geometry), this represents the integral over the full path (forward AND return), not divided by 2. Typical values range from \(10^{18}\) to \(10^{21}\) m⁻² depending on plasma density and chord length. Multiple chords can be inverted tomographically to reconstruct radial density profiles.
Unit: m^-2
Status: Draft
Tags: interferometry, calibrated, line-integrated, measured, time-dependent
electron_volume_averaged_density¶
Volume-averaged electron density estimated from multiple interferometer chords.
Volume-averaged electron number density estimated from multiple interferometer line-integrated measurements. Computed by combining data from multiple chords with different spatial coverage, typically using Abel inversion or tomographic reconstruction followed by volumetric integration:
where \(V\) is the plasma volume. This global quantity is used for plasma inventory calculations, performance assessment, and comparison with other volume-averaged measurements (e.g., from diamagnetic loops). Uncertainty increases with fewer chords and non-uniform spatial coverage.
Unit: m^-3
Status: Draft
Tags: interferometry, derived, time-dependent, volume-average
measured_faraday_rotation_angle¶
Measured Faraday rotation angle used in equilibrium reconstruction.
Faraday rotation angle \(\theta_F\) of polarized electromagnetic wave measured by polarimetry diagnostic. Rotation is proportional to line-integrated parallel magnetic field and electron density: \(\theta_F = \frac{e^3 \lambda^2}{8\pi^2 \epsilon_0 m_e^2 c^2} \int n_e B_{\parallel} dl\). Provides constraint on poloidal field and current profile in reconstruction.
Unit: rad
Status: Draft
Tags: interferometry, equilibrium-reconstruction, measured
path_length_variation_from_interferometer_beam¶
Optical path length variation due to plasma refractive index changes.
Optical path length variation caused by plasma-induced changes in the refractive index along the interferometer beam path. Related to the phase shift by:
where \(\lambda\) is the wavelength and \(\Delta \phi\) is the measured phase shift. This quantity represents the effective physical path length change due to the plasma's dispersive properties. For typical tokamak plasmas with \(n_e \sim 10^{19}\) m⁻³, path length variations are on the order of micrometers to millimeters depending on wavelength and chord geometry.
Unit: m
Status: Draft
Tags: interferometry, derived, measured, time-dependent
phase_from_interferometer_beam¶
Phase shift measured by interferometer, corrected for fringe jumps.
Interferometric phase shift measured by the diagnostic system, with 2π fringe-jump corrections applied. The phase shift is related to line-integrated electron density through the dispersion relation:
where \(r_e = 2.818 \times 10^{-15}\) m is the classical electron radius, \(\lambda\) is the laser wavelength, and the integral is along the beam path. Fringe jump correction algorithms unwrap the phase to provide continuous measurements through density transients. Raw phase data may contain discontinuities; this corrected version should be continuous and monotonic during plasma buildup.
Unit: rad
Status: Draft
Tags: interferometry, calibrated, measured, time-dependent
phase_to_electron_line_integrated_density_conversion_factor_of_interferometer_beam¶
Conversion factor from measured phase to line-integrated electron density.
Calibration factor converting interferometric phase measurements (in radians) to line-integrated electron density (in m⁻²). Derived from the dispersion relation for electromagnetic wave propagation through plasma:
where \(C = \frac{2}{r_e \lambda}\) is this conversion factor, \(r_e = 2.818 \times 10^{-15}\) m is the classical electron radius, and \(\lambda\) is the wavelength. For example, at λ = 10.6 μm (CO₂ laser), \(C \approx 6.7 \times 10^{19}\) m⁻² rad⁻¹. This factor is wavelength-specific and must be applied separately for each interferometer channel or wavelength.
Unit: m^-2.rad^-1
Status: Draft
Tags: interferometry, calibrated
position_of_first_point_of_interferometer_beam¶
Position vector of the first point defining interferometer line of sight.
Three-dimensional position vector (R, Z, φ) of the first geometric point defining an interferometer beam line of sight in cylindrical coordinates. Components are:
- radial_position_of_first_point_of_interferometer_beam (R coordinate, meters)
- vertical_position_of_first_point_of_interferometer_beam (Z coordinate, meters)
- toroidal_angle_of_first_point_of_interferometer_beam (φ coordinate, radians)
This vector specifies the spatial location of the beam source or starting endpoint for line-integrated density measurements.
Unit: m
Status: Draft
Tags: interferometry, cylindrical-coordinates, local-measurement
position_of_second_point_of_interferometer_beam¶
Position vector of the second point defining interferometer line of sight.
Three-dimensional position vector (R, Z, φ) of the second geometric point defining an interferometer beam line of sight. For non-reflected beams, this is the detector location. For reflected beams, this is the retroreflector position. Components are: - radial_position_of_second_point_of_interferometer_beam - vertical_position_of_second_point_of_interferometer_beam - toroidal_angle_of_second_point_of_interferometer_beam
The line segment connecting first and second position vectors defines the primary beam path through the plasma.
Unit: m
Status: Draft
Tags: interferometry, cylindrical-coordinates, local-measurement
position_of_third_point_of_interferometer_beam¶
Position vector of the third point defining reflected interferometer line of sight.
Three-dimensional position vector (R, Z, φ) of the third geometric point defining a reflected interferometer beam line of sight. Used only for retroreflector-based systems where the beam traverses the plasma twice (forward and return paths). Components are:
- radial_position_of_third_point_of_interferometer_beam
- vertical_position_of_third_point_of_interferometer_beam
- toroidal_angle_of_third_point_of_interferometer_beam
This vector represents the final detector location after beam reflection.
Unit: m
Status: Draft
Tags: interferometry, cylindrical-coordinates, local-measurement
radial_position_of_first_point_of_interferometer_beam¶
Major radius of the first point defining interferometer line of sight.
Radial coordinate (major radius R) of the first geometric point defining an interferometer beam line of sight in cylindrical coordinates (R, Z, φ). For non-reflected beams, the first point is typically the laser source location. For reflected beams (triple-point geometry), this point marks one end of the beam path. Accurate positioning is critical for calculating the geometric path length and interpreting line-integrated density measurements.
Unit: m
Status: Draft
Tags: interferometry, cylindrical-coordinates, local-measurement
radial_position_of_second_point_of_interferometer_beam¶
Major radius of the second point defining interferometer line of sight.
Radial coordinate (major radius R) of the second geometric point defining an interferometer beam line of sight. For non-reflected beams (two-point geometry), this is the detector location opposite the source. For reflected beams (three-point geometry), this is the intermediate reflection point (e.g., retroreflector position). The line connecting first and second points defines the beam path used for line-integrated density measurements.
Unit: m
Status: Draft
Tags: interferometry, cylindrical-coordinates, local-measurement
radial_position_of_third_point_of_interferometer_beam¶
Major radius of the third point defining reflected interferometer line of sight.
Radial coordinate (major radius R) of the third geometric point defining a reflected interferometer beam line of sight. This point is only used for reflected beam configurations (retroreflector-based systems) where the beam traverses the plasma twice. The third point typically represents the final detector location after reflection at the second point. The complete path is: first point → second point (reflection) → third point.
Unit: m
Status: Draft
Tags: interferometry, cylindrical-coordinates, local-measurement
reconstructed_faraday_rotation_angle¶
Reconstructed Faraday angle from equilibrium solution along diagnostic chord.
Faraday rotation angle \(\theta_F\) calculated from reconstructed equilibrium by integrating magnetic field and density along polarimetry chord. Comparison with measured value assesses equilibrium reconstruction quality and poloidal field accuracy.
Unit: rad
Status: Draft
Tags: interferometry, equilibrium-reconstruction, reconstructed
toroidal_angle_of_first_point_of_interferometer_beam¶
Toroidal angle of the first point defining interferometer line of sight.
Toroidal angle coordinate (φ) of the first geometric point defining an interferometer beam line of sight in cylindrical coordinates (R, Z, φ). The angle is measured counter-clockwise when viewing from above, following standard tokamak conventions. This coordinate, together with R and Z, fully specifies the spatial location of the beam endpoint or source position.
Unit: rad
Status: Draft
Tags: interferometry, cylindrical-coordinates, local-measurement
toroidal_angle_of_second_point_of_interferometer_beam¶
Toroidal angle of the second point defining interferometer line of sight.
Toroidal angle coordinate (φ) of the second geometric point defining an interferometer beam line of sight. Measured counter-clockwise when viewing from above. Together with the corresponding R and Z coordinates, this defines the second spatial endpoint of the measurement chord.
Unit: rad
Status: Draft
Tags: interferometry, cylindrical-coordinates, local-measurement
toroidal_angle_of_third_point_of_interferometer_beam¶
Toroidal angle of the third point defining reflected interferometer line of sight.
Toroidal angle coordinate (φ) of the third geometric point defining a reflected interferometer beam line of sight. Used only for reflected beam configurations. Measured counter-clockwise when viewing from above.
Unit: rad
Status: Draft
Tags: interferometry, cylindrical-coordinates, local-measurement
vertical_position_of_first_point_of_interferometer_beam¶
Height (Z coordinate) of the first point defining interferometer line of sight.
Vertical coordinate (height Z) of the first geometric point defining an interferometer beam line of sight in cylindrical coordinates (R, Z, φ). Measured relative to the machine midplane reference level. This coordinate defines the vertical position of the beam endpoint or source, completing the (R, Z, φ) triplet for spatial localization.
Unit: m
Status: Draft
Tags: interferometry, cylindrical-coordinates, local-measurement
vertical_position_of_second_point_of_interferometer_beam¶
Height (Z coordinate) of the second point defining interferometer line of sight.
Vertical coordinate (height Z) of the second geometric point defining an interferometer beam line of sight. This coordinate completes the (R, Z, φ) specification for the second spatial point along the measurement path.
Unit: m
Status: Draft
Tags: interferometry, cylindrical-coordinates, local-measurement
vertical_position_of_third_point_of_interferometer_beam¶
Height (Z coordinate) of the third point defining reflected interferometer line of sight.
Vertical coordinate (height Z) of the third geometric point defining a reflected interferometer beam line of sight. Used only for reflected beam configurations to complete the (R, Z, φ) specification of the final detector location.
Unit: m
Status: Draft
Tags: interferometry, cylindrical-coordinates, local-measurement
wavelength_of_interferometer_beam¶
Wavelength of laser light used for interferometry measurement.
Wavelength of the laser beam used for interferometric density measurements. Common interferometer wavelengths include 10.6 μm (CO₂ lasers), 632.8 nm (HeNe lasers), and 1064 nm (Nd:YAG lasers). The wavelength determines the phase sensitivity to electron density through the dispersion relation. Multiple wavelengths may be used simultaneously (multi-chord or multi-color interferometry) to separate vibrational effects from plasma density changes or to resolve higher density plasmas.
Unit: m
Status: Draft
Tags: interferometry, calibrated
Magnetics¶
area_of_poloidal_magnetic_field_probe¶
Effective sensing area of a single turn of poloidal field probe coil.
Cross-sectional area \(A\) of each turn in the poloidal magnetic field probe sensor coil. The total effective sensing area is obtained by multiplying by the number of turns \(N\).
This parameter is essential for relating measured voltage to magnetic field changes via Faraday's law:
where \(B_n\) is the magnetic field component along the sensor normal axis and \(t\) is time. Accurate calibration of the area is critical for quantitative field measurements.
Unit: m^2
Status: Draft
Tags: magnetics, calibrated
area_of_toroidal_magnetic_field_probe¶
Effective sensing area of a single turn of toroidal field probe coil.
Cross-sectional area \(A\) of each turn in the toroidal magnetic field probe sensor coil. The total effective sensing area is \(N A\) where \(N\) is the number of turns.
Relates measured voltage to field changes via Faraday's law:
where \(B_n\) is the field component along the sensor normal. Essential for calibration and quantitative field measurements.
Unit: m^2
Status: Draft
Tags: magnetics, calibrated
diamagnetic_flux¶
Diamagnetic flux measured by diamagnetic loop diagnostic.
Diamagnetic flux \(\Phi_{dia}\) measured by a diamagnetic loop encircling the plasma. This quantity is directly related to the plasma stored energy.
The diamagnetic flux measures the reduction in poloidal flux linkage due to plasma pressure (diamagnetic effect). For a large-aspect-ratio circular plasma:
where \(R_0\) is the major radius, \(p\) is plasma pressure, and \(W_{th}\) is the thermal stored energy.
More generally, the diamagnetic flux is related to the poloidal beta:
Diamagnetic loops are toroidally symmetric coils that measure the difference in poloidal flux with and without plasma. Used for real-time stored energy monitoring and plasma control.
Unit: Wb
Status: Draft
Tags: magnetics, measured, time-dependent
length_of_poloidal_magnetic_field_probe¶
Length of sensing coil along sensor normal axis of poloidal field probe.
Physical length \(L\) of the sensor coil along its normal axis direction. This defines the spatial extent over which the magnetic field is averaged.
The measured field represents a volume average:
where \(V = N A L\) is the total sensing volume (\(N\) = number of turns, \(A\) = area per turn), and \(\mathbf{n}\) is the sensor normal direction. Longer sensors provide better signal-to-noise but reduce spatial resolution.
Unit: m
Status: Draft
Tags: magnetics, calibrated
length_of_toroidal_magnetic_field_probe¶
Length of sensing coil along sensor normal axis of toroidal field probe.
Physical length \(L\) of the sensor coil along its normal axis direction. Defines the spatial extent over which the magnetic field is averaged.
The measured field is a volume average over the sensing region of volume \(V = N A L\), where \(N\) is the number of turns and \(A\) is the area per turn.
Unit: m
Status: Draft
Tags: magnetics, calibrated
magnetic_field_from_poloidal_magnetic_field_probe¶
Magnetic field component measured by poloidal field probe along sensor normal axis.
Magnetic field component \(B_n = \mathbf{B} \cdot \mathbf{n}\) measured along the sensor normal axis direction \(\mathbf{n}\), averaged over the probe sensing volume.
The sensor normal direction is defined by poloidal and toroidal orientation angles:
Typically obtained by integrating the measured voltage:
where \(N\) is the number of turns, \(A\) is the area per turn, and \(V\) is the measured voltage. Used for plasma equilibrium reconstruction and position control.
Unit: T
Status: Draft
Tags: magnetics, measured, time-dependent
magnetic_field_from_toroidal_magnetic_field_probe¶
Magnetic field component measured by toroidal field probe along sensor normal axis.
Magnetic field component \(B_n = \mathbf{B} \cdot \mathbf{n}\) measured along the sensor normal axis direction, averaged over the probe sensing volume.
Obtained by integrating the measured voltage:
where \(N\) is the number of turns, \(A\) is the area per turn, and \(V\) is the measured voltage.
Toroidal field probes are used to measure toroidal field ripple, error fields, and field variations due to ferritic inserts or asymmetries in the toroidal field coil system.
Unit: T
Status: Draft
Tags: magnetics, measured, time-dependent
measured_poloidal_component_of_magnetic_field_from_poloidal_magnetic_field_probe¶
Measured poloidal magnetic field from probe used in equilibrium reconstruction.
Poloidal magnetic field component \(B_{pol}\) measured by poloidal field probe diagnostic, used as constraint in equilibrium reconstruction. Measurement is field component along probe sensor normal axis, obtained by integrating induced voltage: \(B(t) = B(t_0) - \frac{1}{NA} \int_{t_0}^{t} V(t') dt'\) where \(N\) is coil turns and \(A\) is effective area. Multiple probes provide spatial mapping for reconstruction algorithms.
Unit: T
Status: Draft
Tags: magnetics, equilibrium-reconstruction, measured
measured_poloidal_magnetic_flux_from_flux_loop¶
Measured poloidal magnetic flux from flux loop used in reconstruction.
Poloidal magnetic flux \(\psi\) measured by flux loop diagnostic, used as constraint in equilibrium reconstruction. Flux defined as \(\psi = \int \mathbf{B}_p \cdot d\mathbf{A}\) over loop area. Sign convention: Positive when normal to loop points downward (negative \(Z\) direction). Fundamental measurement for equilibrium reconstruction and plasma current estimation.
Unit: Wb
Status: Draft
Tags: magnetics, equilibrium-reconstruction, measured
number_of_turns_of_poloidal_magnetic_field_probe¶
Number of turns in the sensing coil of poloidal field probe.
Number of wire turns \(N\) in the poloidal magnetic field probe coil, including sign. Negative values can be used to indicate coil winding direction.
The induced voltage is proportional to the number of turns:
where \(A\) is the area per turn and \(B_n\) is the field component along the sensor normal. More turns increase signal amplitude but also increase inductance and may reduce frequency response.
Status: Draft
Tags: magnetics, calibrated
number_of_turns_of_toroidal_magnetic_field_probe¶
Number of turns in the sensing coil of toroidal field probe.
Number of wire turns \(N\) in the toroidal magnetic field probe coil, including sign convention for winding direction.
The induced voltage is proportional to the number of turns:
where \(A\) is the area per turn. More turns increase signal strength but may affect frequency response due to increased inductance.
Status: Draft
Tags: magnetics, calibrated
poloidal_angle_of_sensor_normal_of_poloidal_magnetic_field_probe¶
Poloidal angle of sensor normal axis orientation of poloidal field probe.
Angle \(\theta_n\) defining the poloidal orientation of the sensor normal axis (vector parallel to the coil axis) with respect to the horizontal plane. This is a clockwise theta-like angle.
Convention: \(\theta_n = 0\) when the sensor normal is fully horizontal and points toward increasing major radius. Values range in \([0, 2\pi]\).
The sensor normal axis direction \(\mathbf{n}\) is:
where \(\phi_n\) is the toroidal angle of the sensor normal. The probe measures the magnetic field component \(\mathbf{B} \cdot \mathbf{n}\) along this direction.
Unit: rad
Status: Draft
Tags: magnetics, local-measurement
poloidal_angle_of_sensor_normal_of_toroidal_magnetic_field_probe¶
Poloidal angle of sensor normal axis orientation of toroidal field probe.
Angle \(\theta_n\) defining the poloidal orientation of the sensor normal axis (vector parallel to the coil axis) with respect to the horizontal plane. This is a clockwise theta-like angle.
Convention: \(\theta_n = 0\) when the sensor normal is fully horizontal and points toward increasing major radius. Values range in \([0, 2\pi]\).
Combined with the toroidal angle of the sensor normal, this fully specifies the orientation of the probe and determines which magnetic field component is measured.
Unit: rad
Status: Draft
Tags: magnetics, local-measurement
poloidal_magnetic_flux_from_flux_loop¶
Poloidal magnetic flux measured by flux loop diagnostic.
Poloidal magnetic flux threading through a flux loop coil, defined as the surface integral of the poloidal magnetic field:
where the integration is over the area enclosed by the loop.
Sign convention: Positive flux when the normal vector to the loop area points downward (negative \(Z\) direction), following right-hand rule with respect to the toroidal direction.
By Faraday's law, the induced voltage in the loop is:
Flux loop measurements are fundamental for equilibrium reconstruction, plasma current estimation, and real-time plasma position control. Partial flux loops can also be used, with appropriate geometric corrections for the unclosed contour.
Unit: Wb
Status: Draft
Tags: magnetics, measured, time-dependent
position_of_flux_loop¶
Position vector of flux loop contour point in cylindrical coordinates.
Three-dimensional position vector \((R, Z, \phi)\) defining a point on a flux loop contour in cylindrical coordinates. Components are radial position (major radius \(R\)), vertical position (height \(Z\)), and toroidal angle (\(\phi\)).
A complete flux loop is described by a sequence of position vectors defining its contour. The loop geometry determines the effective area for poloidal flux measurements via Faraday's law:
where \(V\) is the induced voltage and \(\psi\) is the poloidal magnetic flux enclosed by the loop.
Unit: m
Status: Draft
Tags: magnetics, cylindrical-coordinates, local-measurement
position_of_poloidal_magnetic_field_probe¶
Position vector of poloidal field probe center in cylindrical coordinates.
Three-dimensional position vector \((R, Z, \phi)\) defining the geometric center of a poloidal magnetic field probe in cylindrical coordinates. Components are radial position (major radius \(R\)), vertical position (height \(Z\)), and toroidal angle (\(\phi\)).
The probe measures magnetic field components along its sensor normal axis at this location. Arrays of probes at different positions enable real-time plasma position control and detailed equilibrium reconstruction.
Unit: m
Status: Draft
Tags: magnetics, cylindrical-coordinates, local-measurement
position_of_toroidal_magnetic_field_probe¶
Position vector of toroidal field probe center in cylindrical coordinates.
Three-dimensional position vector \((R, Z, \phi)\) defining the geometric center of a toroidal magnetic field probe in cylindrical coordinates. Components are radial position (major radius \(R\)), vertical position (height \(Z\)), and toroidal angle (\(\phi\)).
The probe measures magnetic field components along its sensor normal axis at this location, typically used to characterize toroidal field ripple and error fields.
Unit: m
Status: Draft
Tags: magnetics, cylindrical-coordinates, local-measurement
radial_position_of_flux_loop¶
Major radius (R coordinate) of flux loop contour point in cylindrical coordinates.
Radial coordinate (major radius \(R\)) defining the spatial location of a point on a flux loop contour. Together with vertical position (\(Z\)) and toroidal angle (\(\phi\)), forms the \((R, Z, \phi)\) triplet describing the flux loop geometry in cylindrical coordinates.
Multiple position points define the complete flux loop contour used for measuring poloidal magnetic flux. The flux measured by the loop is defined as:
where the integration is over the surface enclosed by the loop. Accurate positioning is critical for equilibrium reconstruction and plasma shape control.
Unit: m
Status: Draft
Tags: magnetics, cylindrical-coordinates, local-measurement
radial_position_of_poloidal_magnetic_field_probe¶
Major radius (R coordinate) of poloidal field probe center in cylindrical coordinates.
Radial coordinate (major radius \(R\)) of the geometric center of a poloidal magnetic field probe coil. Together with vertical position (\(Z\)) and toroidal angle (\(\phi\)), defines the \((R, Z, \phi)\) position of the probe in cylindrical coordinates.
The probe measures the magnetic field component along its sensor normal axis direction. Accurate positioning is essential for interpreting the field measurements and for plasma equilibrium reconstruction using multiple probe arrays.
Unit: m
Status: Draft
Tags: magnetics, cylindrical-coordinates, local-measurement
radial_position_of_toroidal_magnetic_field_probe¶
Major radius (R coordinate) of toroidal field probe center in cylindrical coordinates.
Radial coordinate (major radius \(R\)) of the geometric center of a toroidal magnetic field probe coil. Together with vertical position (\(Z\)) and toroidal angle (\(\phi\)), defines the \((R, Z, \phi)\) position of the probe in cylindrical coordinates.
Toroidal field probes measure field components along their sensor normal direction and are used to detect variations in the toroidal field due to coil ripple, ferritic inserts, or error fields.
Unit: m
Status: Draft
Tags: magnetics, cylindrical-coordinates, local-measurement
reconstructed_poloidal_component_of_magnetic_field_from_poloidal_magnetic_field_probe¶
Reconstructed poloidal field from equilibrium solution at probe location.
Poloidal magnetic field component \(B_{pol}\) calculated from reconstructed equilibrium at poloidal field probe location. Used to assess goodness-of-fit between equilibrium model and diagnostic measurements. Difference between reconstructed and measured values indicates reconstruction residuals.
Unit: T
Status: Draft
Tags: magnetics, equilibrium-reconstruction, reconstructed
reconstructed_poloidal_magnetic_flux_from_flux_loop¶
Reconstructed poloidal flux from equilibrium solution through flux loop.
Poloidal magnetic flux \(\psi\) calculated from reconstructed equilibrium by integrating poloidal field over flux loop area. Difference from measured value indicates reconstruction residual and solution quality for this diagnostic channel.
Unit: Wb
Status: Draft
Tags: magnetics, equilibrium-reconstruction, reconstructed
reference_radial_position_of_vacuum_toroidal_magnetic_field¶
Reference major radius where vacuum toroidal magnetic field is specified.
Reference major radius \(R_0\) where the vacuum toroidal magnetic field \(B_0\) is defined. Typically chosen at the machine geometric center or vessel midplane. Together with toroidal_component_of_vacuum_magnetic_field_at_reference_position, defines the vacuum toroidal field profile \(B_{tor}(R) \approx B_0 R_0 / R\) for equilibrium calculations and flux coordinate normalization.
Unit: m
Status: Draft
Tags: magnetics, calibrated
toroidal_angle_of_poloidal_magnetic_field_probe¶
Toroidal angle (φ coordinate) of poloidal field probe center in cylindrical coordinates.
Toroidal angle \(\phi\) specifying the azimuthal position of a poloidal magnetic field probe center in cylindrical coordinates. The angle is measured counter-clockwise when viewing from above, with \(\phi = 0\) typically defined at a machine-specific reference location.
Together with radial position (\(R\)) and vertical position (\(Z\)), this forms the complete \((R, Z, \phi)\) position triplet. Multiple probes distributed toroidally enable assessment of toroidal field asymmetries and plasma shape variations.
Unit: rad
Status: Draft
Tags: magnetics, cylindrical-coordinates, local-measurement
toroidal_angle_of_sensor_normal_of_poloidal_magnetic_field_probe¶
Toroidal angle of sensor normal axis projection of poloidal field probe.
Angle \(\phi_n\) of the horizontal projection of the sensor normal axis with respect to the direction of increasing major radius $ abla R$. Measured counter-clockwise from above (consistent with toroidal coordinate convention).
Convention: Values taken modulo \(\pi\) within \((-\pi/2, \pi/2]\). \(\phi_n = 0\) when the projected sensor normal is parallel to $ abla R$ (radially outward), \(\phi_n = \pi/2\) when parallel to $ abla\phi$ (toroidal direction).
This angle, combined with the poloidal angle, fully defines the sensor normal direction and determines which magnetic field component is measured.
Unit: rad
Status: Draft
Tags: magnetics, local-measurement
toroidal_angle_of_sensor_normal_of_toroidal_magnetic_field_probe¶
Toroidal angle of sensor normal axis projection of toroidal field probe.
Angle \(\phi_n\) of the horizontal projection of the sensor normal axis with respect to the direction of increasing major radius $ abla R$. Measured counter-clockwise from above.
Convention: Values taken modulo \(\pi\) within \((-\pi/2, \pi/2]\). \(\phi_n = 0\) when the projected sensor normal is parallel to $ abla R$ (radially outward), \(\phi_n = \pi/2\) when parallel to $ abla\phi$ (toroidal direction).
For toroidal field probes, the sensor normal is often oriented to measure the toroidal field component.
Unit: rad
Status: Draft
Tags: magnetics, local-measurement
toroidal_angle_of_toroidal_magnetic_field_probe¶
Toroidal angle (φ coordinate) of toroidal field probe center in cylindrical coordinates.
Toroidal angle \(\phi\) specifying the azimuthal position of a toroidal magnetic field probe center. The angle is measured counter-clockwise when viewing from above.
Distributing toroidal field probes at different toroidal angles enables measurement of toroidal field ripple and detection of 3D field perturbations from error fields or resonant magnetic perturbations (RMPs).
Unit: rad
Status: Draft
Tags: magnetics, cylindrical-coordinates, local-measurement
toroidal_component_of_vacuum_magnetic_field_at_reference_position¶
Vacuum toroidal magnetic field component at reference position.
Vacuum toroidal magnetic field \(B_0\) at the reference major radius \(R_0\). Sign convention: Positive when anti-clockwise viewing from above (positive toroidal angle direction). The product \(R_0 B_0\) characterizes the vacuum field profile \(B_{tor}(R) = B_0 R_0 / R\). Used in flux coordinate normalization and equilibrium reconstruction. Must be consistent with actual toroidal field coil currents.
Unit: T
Status: Draft
Tags: magnetics, time-dependent
vertical_position_of_flux_loop¶
Height (Z coordinate) of flux loop contour point in cylindrical coordinates.
Vertical coordinate (height \(Z\)) defining the spatial location of a point on a flux loop contour. Together with radial position (\(R\)) and toroidal angle (\(\phi\)), forms the \((R, Z, \phi)\) triplet describing the flux loop geometry in cylindrical coordinates.
Multiple position points define the complete flux loop contour used for measuring poloidal magnetic flux. The vertical positioning is essential for determining the loop's orientation relative to the plasma and for calculating the effective area for flux linkage measurements.
Unit: m
Status: Draft
Tags: magnetics, cylindrical-coordinates, local-measurement
vertical_position_of_poloidal_magnetic_field_probe¶
Height (Z coordinate) of poloidal field probe center in cylindrical coordinates.
Vertical coordinate (height \(Z\)) of the geometric center of a poloidal magnetic field probe coil. Together with radial position (\(R\)) and toroidal angle (\(\phi\)), defines the \((R, Z, \phi)\) position of the probe in cylindrical coordinates.
Vertical positioning of probe arrays is critical for measuring plasma vertical position and for magnetic equilibrium reconstruction using the measured field patterns.
Unit: m
Status: Draft
Tags: magnetics, cylindrical-coordinates, local-measurement
vertical_position_of_toroidal_magnetic_field_probe¶
Height (Z coordinate) of toroidal field probe center in cylindrical coordinates.
Vertical coordinate (height \(Z\)) of the geometric center of a toroidal magnetic field probe coil. Together with radial position (\(R\)) and toroidal angle (\(\phi\)), defines the complete probe position in cylindrical coordinates.
Vertical positioning allows characterization of the vertical structure of toroidal field variations and error fields.
Unit: m
Status: Draft
Tags: magnetics, cylindrical-coordinates, local-measurement
voltage_from_poloidal_magnetic_field_probe¶
Voltage induced across terminals of poloidal field probe coil.
Voltage \(V\) induced across the terminals of a poloidal magnetic field probe coil due to time-varying magnetic flux. Related to the time derivative of magnetic field by Faraday's law:
where \(N\) is the number of turns, \(A\) is the area per turn, and \(B_n\) is the magnetic field component along the sensor normal axis.
The voltage signal is typically integrated to obtain the magnetic field:
Direct voltage measurements are useful for fast timescale phenomena and for diagnosing sensor functionality.
Unit: V
Status: Draft
Tags: magnetics, measured, raw-data, time-dependent
Radiation Diagnostics¶
brightness_from_soft_xray_detector¶
Specific intensity (power per unit area per unit solid angle) measured by soft X-ray detector.
Brightness (specific intensity) measured by the soft X-ray detector, defined as the power flux per unit solid angle per unit area: \(B = P / (A \Omega)\) where \(P\) is power, \(A\) is detector area, and \(\Omega\) is solid angle. This is the étendue-normalized signal, obtained by dividing the measured power by the detector's étendue. Brightness is the fundamental radiometric quantity for tomographic reconstruction, as it is independent of the detector's geometric parameters. Units are W·m⁻²·sr⁻¹. The brightness is related to plasma emissivity through line integration along the viewing chord.
Unit: W.m^-2.sr^-1
Status: Draft
Tags: radiation-diagnostics, measured, time-dependent
etendue_of_soft_xray_detector¶
Geometric extent (étendue) of soft X-ray detector optical system.
Étendue (geometric extent) of the soft X-ray detector's optical system, defined as the product of the effective collection area and solid angle: \(G = A \Omega\) where \(A\) is the detector area and \(\Omega\) is the solid angle of acceptance. The étendue characterizes the light-gathering power of the optical system and is an important calibration parameter for converting measured signals to absolute brightness values. Units are m²·sr. Larger étendue improves signal-to-noise ratio but reduces spatial resolution. For pinhole-based systems, \(G \approx A_{detector} A_{pinhole}/d^2\) where \(d\) is the pinhole-to-detector distance.
Unit: m^2.sr
Status: Draft
Tags: radiation-diagnostics, calibrated, local-measurement
lower_bound_of_soft_xray_detector_energy_band¶
Lower energy threshold of soft X-ray detector sensitive energy band.
Lower energy boundary of the soft X-ray detector's sensitive energy band. Soft X-rays typically span ~0.1-20 keV photon energies, corresponding to plasma temperatures and impurity line emission in the soft X-ray range. The energy band is determined by detector material properties (e.g., Si, GaAs), filters (Be, Al foils), and photon absorption characteristics. Multiple energy bands allow spectroscopic analysis and separation of different radiation contributions (bremsstrahlung, line emission).
Unit: eV
Status: Draft
Tags: radiation-diagnostics, calibrated
position_of_soft_xray_detector_line_of_sight_first_point¶
Three-dimensional position vector of first point defining soft X-ray detector line of sight.
Three-dimensional position vector (R, Z, φ) of the first geometric point defining a soft X-ray detector line of sight in cylindrical coordinates. Components are: - radial_position_of_soft_xray_detector_line_of_sight_first_point - vertical_position_of_soft_xray_detector_line_of_sight_first_point - toroidal_angle_of_soft_xray_detector_line_of_sight_first_point
This vector typically represents the detector location for tomographic systems. Note: toroidal_angle has units of radians while the vector unit is meters for (R, Z) components.
Unit: m
Status: Draft
Tags: radiation-diagnostics, cylindrical-coordinates, local-measurement
position_of_soft_xray_detector_line_of_sight_second_point¶
Three-dimensional position vector of second point defining soft X-ray detector line of sight.
Three-dimensional position vector (R, Z, φ) of the second geometric point defining a soft X-ray detector line of sight in cylindrical coordinates. Components are: - radial_position_of_soft_xray_detector_line_of_sight_second_point - vertical_position_of_soft_xray_detector_line_of_sight_second_point - toroidal_angle_of_soft_xray_detector_line_of_sight_second_point
The line segment connecting first and second position vectors defines the viewing chord through the plasma. For pinhole systems, this represents the pinhole location. Note: toroidal_angle has units of radians while the vector unit is meters for (R, Z) components.
Unit: m
Status: Draft
Tags: radiation-diagnostics, cylindrical-coordinates, local-measurement
power_from_soft_xray_detector¶
Total radiant power received by soft X-ray detector.
Total radiant power received by the soft X-ray detector in a specific energy band. This is the raw or calibrated signal proportional to the photon flux integrated over the detector area and acceptance solid angle. Power is related to brightness by: \(P = B \cdot G\) where \(B\) is brightness and \(G\) is the detector's étendue. For absolute measurements, proper calibration accounts for detector efficiency, filter transmission, and electronic gain. Power signals are used for MHD activity monitoring, radiation loss estimates, and tomographic reconstruction after normalization by étendue.
Unit: W
Status: Draft
Tags: radiation-diagnostics, measured, time-dependent
radial_position_of_soft_xray_detector_line_of_sight_first_point¶
Major radius (R coordinate) of first point defining soft X-ray detector line of sight.
Radial coordinate (major radius R) of the first geometric point defining a soft X-ray detector line of sight in cylindrical (R, Z, φ) coordinates. For tomographic reconstruction systems, this typically represents the detector location. The line connecting first and second points defines the viewing chord through the plasma used for line-integrated soft X-ray emissivity measurements. Accurate positioning is critical for tomographic inversion and plasma shape reconstruction.
Unit: m
Status: Draft
Tags: radiation-diagnostics, cylindrical-coordinates, local-measurement
radial_position_of_soft_xray_detector_line_of_sight_second_point¶
Major radius (R coordinate) of second point defining soft X-ray detector line of sight.
Radial coordinate (major radius R) of the second geometric point defining a soft X-ray detector line of sight in cylindrical (R, Z, φ) coordinates. The line segment connecting the first and second points defines the viewing chord through the plasma. For pinhole camera systems, this typically represents the pinhole location. The chord geometry determines which plasma regions contribute to the measured signal.
Unit: m
Status: Draft
Tags: radiation-diagnostics, cylindrical-coordinates, local-measurement
toroidal_angle_of_soft_xray_detector_line_of_sight_first_point¶
Toroidal angle (φ coordinate) of first point defining soft X-ray detector line of sight.
Toroidal angle φ of the first geometric point defining a soft X-ray detector line of sight in cylindrical (R, Z, φ) coordinates. The angle is measured counter-clockwise when viewing from above, with φ = 0 typically aligned with a reference toroidal location. Together with R and Z coordinates, this defines the spatial location of the detector or first measurement point. Used in tomographic reconstruction to account for toroidal variations in emissivity.
Unit: rad
Status: Draft
Tags: radiation-diagnostics, cylindrical-coordinates, local-measurement
toroidal_angle_of_soft_xray_detector_line_of_sight_second_point¶
Toroidal angle (φ coordinate) of second point defining soft X-ray detector line of sight.
Toroidal angle φ of the second geometric point defining a soft X-ray detector line of sight in cylindrical (R, Z, φ) coordinates. Measured counter-clockwise when viewing from above. The difference between first and second point toroidal angles determines the toroidal extent of the viewing chord, which is typically small for localized measurements but may be significant for tangential viewing geometries.
Unit: rad
Status: Draft
Tags: radiation-diagnostics, cylindrical-coordinates, local-measurement
upper_bound_of_soft_xray_detector_energy_band¶
Upper energy threshold of soft X-ray detector sensitive energy band.
Upper energy boundary of the soft X-ray detector's sensitive energy band. The upper limit defines the maximum photon energy to which the detector is sensitive, typically determined by material photoelectric absorption cross-sections and detector thickness. For tomographic reconstruction, multiple overlapping energy bands provide temperature and impurity density profile information. Typical upper bounds: 5-20 keV for core plasma diagnostics.
Unit: eV
Status: Draft
Tags: radiation-diagnostics, calibrated
vertical_position_of_soft_xray_detector_line_of_sight_first_point¶
Height (Z coordinate) of first point defining soft X-ray detector line of sight.
Vertical coordinate (height Z) of the first geometric point defining a soft X-ray detector line of sight in cylindrical (R, Z, φ) coordinates. The Z coordinate is measured from the machine midplane, with positive values above and negative values below. This vertical position, combined with R and φ, fully specifies the detector location in 3D space for tomographic reconstruction algorithms.
Unit: m
Status: Draft
Tags: radiation-diagnostics, cylindrical-coordinates, local-measurement
vertical_position_of_soft_xray_detector_line_of_sight_second_point¶
Height (Z coordinate) of second point defining soft X-ray detector line of sight.
Vertical coordinate (height Z) of the second geometric point defining a soft X-ray detector line of sight in cylindrical (R, Z, φ) coordinates. Together with the first point's Z coordinate, this determines the vertical viewing angle and which plasma regions (core, edge, divertor) are observed along the line of sight. Vertical positioning is crucial for distinguishing between core and edge emissivity contributions.
Unit: m
Status: Draft
Tags: radiation-diagnostics, cylindrical-coordinates, local-measurement
Spectroscopy¶
atomic_mass_number_of_isotope¶
Atomic mass number (A) of an isotope or element in atomic mass units.
Atomic mass number A of an isotope, representing the total number of protons and neutrons in the nucleus, expressed in unified atomic mass units (u). For hydrogen isotopes: \(A_H = 1\), \(A_D = 2\), \(A_T = 3\). For helium isotopes: \(A_{^3He} = 3\), \(A_{^4He} = 4\). Used to identify isotopes in spectroscopic measurements and calculate mass-dependent properties like gyroradius and neutral penetration depth. Combined with nuclear charge number Z determines the isotope uniquely.
Unit: u
Status: Draft
Tags: spectroscopy
central_wavelength_of_spectral_line_from_spectrometer¶
Central wavelength of an identified spectral line after processing.
Central wavelength of a processed spectral line identified in the measured spectrum. Determined by fitting the line profile (typically Gaussian or Voigt) to the measured intensity distribution. The central wavelength can be used to identify atomic/ionic species and measure Doppler shifts for velocity and temperature diagnostics. Wavelength shifts from the rest wavelength indicate plasma motion or thermal broadening effects.
Unit: m
Status: Draft
Tags: spectroscopy, calibrated, measured
cold_neutral_fraction_of_isotope¶
Fraction of cold neutrals relative to total neutrals for a specific isotope.
Fraction of cold neutrals relative to the total neutral population for a specific isotope, defined as \(f_{cold} = n_{cold} / (n_{cold} + n_{hot})\) where \(n_{cold}\) and \(n_{hot}\) are the cold and hot neutral densities respectively. Dimensionless quantity between 0 and 1. Cold neutrals typically originate from molecular dissociation and wall recycling (energies <1 eV), while hot neutrals come from charge exchange with plasma ions (energies ~keV). Determined from spectral line shape analysis including Doppler broadening and line intensities.
Status: Draft
Tags: spectroscopy, measured, time-dependent
cold_neutral_temperature_of_isotope¶
Temperature characterizing the cold neutral population for a specific isotope.
Temperature characterizing the energy distribution of the cold neutral population for a specific isotope, typically <1 eV. Determined from Doppler broadening analysis of spectral lines, where the line width \(\Delta\lambda\) relates to temperature as \(\Delta\lambda / \lambda = \sqrt{2kT/mc^2}\), with \(m\) the neutral mass and \(c\) the speed of light. Cold neutrals originate primarily from molecular dissociation and wall recycling processes. Temperature values typically 0.1-1 eV in edge and divertor regions.
Unit: eV
Status: Draft
Tags: spectroscopy, measured, time-dependent
hot_neutral_fraction_of_isotope¶
Fraction of hot neutrals relative to total neutrals for a specific isotope.
Fraction of hot neutrals relative to the total neutral population for a specific isotope, defined as \(f_{hot} = n_{hot} / (n_{cold} + n_{hot})\). Dimensionless quantity between 0 and 1, where \(f_{hot} + f_{cold} = 1\). Hot neutrals are produced by charge exchange between plasma ions and background neutrals, carrying energies comparable to ion temperature (typically tens of eV to keV). Extracted from spectral line shape analysis using multi-Gaussian fits to separate cold and hot components.
Status: Draft
Tags: spectroscopy, measured, time-dependent
hot_neutral_temperature_of_isotope¶
Temperature characterizing the hot neutral population for a specific isotope.
Temperature characterizing the energy distribution of the hot neutral population for a specific isotope, typically tens of eV to keV. Determined from the broad Doppler-broadened component of spectral lines. Hot neutrals are produced by charge exchange: \(Ion^+ + Neutral^0 \rightarrow Ion^0 + Neutral^+\), carrying away energy comparable to the ion temperature. Multi-component line fitting separates hot and cold populations. Hot neutral temperature approximates local ion temperature in regions where charge exchange is active.
Unit: eV
Status: Draft
Tags: spectroscopy, measured, time-dependent
intensity_of_spectral_line_from_spectrometer¶
Uncalibrated intensity of an identified spectral line integrated over its wavelength range.
Uncalibrated intensity of a specific spectral line, integrated over the wavelength extent of the line. Represents the total photoelectron count rate for the line after background subtraction but before absolute radiometric calibration. Units: counts per second (s⁻¹). Useful for qualitative monitoring of line emission trends and relative intensity comparisons when absolute calibration is not required or available.
Unit: s^-1
Status: Draft
Tags: spectroscopy, measured, raw-data, time-dependent
intensity_spectrum_from_spectrometer¶
Uncalibrated intensity spectrum measured by spectrometer detector.
Intensity spectrum representing the number of photoelectrons detected per unit time by each wavelength pixel of the spectrometer channel. This is raw or minimally processed data that includes electronic gain compensation and relative channel calibration but not absolute radiometric calibration. Units are counts per second (s⁻¹). Used for qualitative analysis or when absolute calibration is unavailable. Convert to calibrated spectral radiance using detector sensitivity and system throughput calibration factors.
Unit: s^-1
Status: Draft
Tags: spectroscopy, measured, raw-data, time-dependent
neutral_density_ratio_of_isotope¶
Ratio of neutral density of an isotope to the sum of all other measured isotope neutral densities.
Ratio of the neutral density of a specific isotope to the summed neutral densities of all other isotopes in the measurement set, defined as \(n_i / \sum_{j eq i} n_j\) where \(n_i\) is the neutral density of isotope \(i\). Dimensionless quantity derived from spectral line intensity ratios of isotope-specific transitions. Used for fuel isotope mix analysis in deuterium-tritium plasmas and wall recycling studies. Typical values: 0.1-10 depending on fueling mix and recycling sources.
Status: Draft
Tags: spectroscopy, measured, time-dependent
nuclear_charge_number_of_isotope¶
Nuclear charge number (Z) of an element in elementary charge units.
Nuclear charge number Z of an element, representing the number of protons in the nucleus, expressed in elementary charge units (e). For hydrogen isotopes (H, D, T): \(Z = 1\). For helium isotopes: \(Z = 2\). This determines the element identity and, together with the atomic mass number A, uniquely identifies the isotope. Essential for spectral line identification as Z determines the electronic structure and emission spectrum.
Unit: e
Status: Draft
Tags: spectroscopy
number_of_atoms_of_element_in_molecule¶
Number of atoms of a specific element present in a molecule.
Number of atoms of a specific element within a molecule. For atomic species this is 1 (e.g., H, D, He). For diatomic molecules: 2 (e.g., H₂, D₂, HD). For more complex molecules, the stoichiometric coefficient for that element (e.g., for CH₄, carbon has 1, hydrogen has 4). Used to interpret molecular spectroscopy and calculate molecular densities from measured emission intensities.
Status: Draft
Tags: spectroscopy
position_of_line_of_sight_first_point_from_spectrometer¶
3D position vector of the first point defining the spectrometer line of sight.
Three-dimensional position vector (R, φ, Z) of the first endpoint defining the spectrometer diagnostic line of sight in cylindrical coordinates. R is the major radius, φ is the toroidal angle (rad), and Z is the height. This vector, together with the second point vector, completely defines the viewing chord geometry through the plasma for line-integrated spectroscopic measurements.
Unit: m
Status: Draft
Tags: spectroscopy, cylindrical-coordinates, local-measurement
position_of_line_of_sight_second_point_from_spectrometer¶
3D position vector of the second point defining the spectrometer line of sight.
Three-dimensional position vector (R, φ, Z) of the second endpoint defining the spectrometer diagnostic line of sight in cylindrical coordinates. Together with the first point, the line segment between these vectors determines the complete diagnostic viewing chord geometry and the spatial integration path for all spectroscopic measurements.
Unit: m
Status: Draft
Tags: spectroscopy, cylindrical-coordinates, local-measurement
radial_position_of_line_of_sight_first_point_from_spectrometer¶
Major radius (R coordinate) of the first point defining the spectrometer line of sight.
Radial coordinate (major radius R) of the first endpoint of the spectrometer diagnostic line of sight in cylindrical coordinates (R, φ, Z). Together with the second point, this defines the viewing chord geometry through the plasma. The line of sight determines the spatial integration volume for emitted radiation measurements. Coordinate convention: R is measured from the tokamak major axis (Z-axis) outward in the horizontal plane.
Unit: m
Status: Draft
Tags: spectroscopy, cylindrical-coordinates, local-measurement
radial_position_of_line_of_sight_second_point_from_spectrometer¶
Major radius (R coordinate) of the second point defining the spectrometer line of sight.
Radial coordinate (major radius R) of the second endpoint of the spectrometer diagnostic line of sight in cylindrical coordinates (R, φ, Z). Together with the first point, this defines the complete viewing chord geometry. The line segment between first and second points determines the spatial integration path for line-integrated spectroscopic measurements.
Unit: m
Status: Draft
Tags: spectroscopy, cylindrical-coordinates, local-measurement
radiance_of_spectral_line_from_spectrometer¶
Calibrated radiance of an identified spectral line integrated over its wavelength range.
Calibrated radiance of a specific spectral line, integrated over the wavelength extent of the line and with background continuum subtracted. Units: \(W \cdot m^{-2} \cdot sr^{-1}\). This integrated line radiance is proportional to the emissivity of the corresponding atomic or ionic transition, which depends on species density, temperature, and excitation/ionization balance. Used for impurity concentration measurements, plasma temperature inference, and particle transport studies.
Unit: W.m^-2.sr^-1
Status: Draft
Tags: spectroscopy, calibrated, measured, time-dependent
signal_to_noise_ratio_from_spectrometer¶
Signal-to-noise ratio for spectroscopic measurements expressed in decibels.
Signal-to-noise ratio quantifying the quality of spectroscopic measurements, expressed in decibels (dB). Calculated as \(\text{SNR}_{dB} = 10 \log_{10}(P_{signal}/P_{noise})\) where \(P_{signal}\) is the spectral power in the band containing lines of interest and \(P_{noise}\) is the power in a reference band without spectral lines. Higher values indicate better measurement quality. Typical values: >10 dB for reliable measurements, >20 dB for high precision analysis. Used to validate measurement quality for isotope ratio analysis and other quantitative diagnostics.
Unit: dB
Status: Draft
Tags: spectroscopy, measured, time-dependent
spectral_radiance_from_spectrometer¶
Calibrated spectral radiance (radiance per unit wavelength) measured by spectrometer.
Calibrated spectral radiance measured by visible light spectrometer, defined as radiant intensity per unit wavelength interval per unit solid angle per unit projected source area. Units: \(W \cdot m^{-2} \cdot sr^{-1} \cdot m^{-1}\) where the final \(m^{-1}\) represents per unit wavelength. Calibration accounts for detector sensitivity, optical throughput, and geometric factors. Used for quantitative analysis of plasma emission including line intensities, continuum radiation, and impurity concentrations.
Unit: W.m^-2.m^-1.sr^-1
Status: Draft
Tags: spectroscopy, calibrated, measured, time-dependent
toroidal_angle_of_line_of_sight_first_point_from_spectrometer¶
Toroidal angle (φ coordinate) of the first point defining the spectrometer line of sight.
Toroidal angle coordinate φ of the first endpoint of the spectrometer diagnostic line of sight in cylindrical coordinates (R, φ, Z). Convention: φ is oriented counter-clockwise when viewing from above (looking down the negative Z-axis), with φ = 0 typically at the machine reference position. Together with R and Z coordinates, defines the 3D position of the line of sight starting point.
Unit: rad
Status: Draft
Tags: spectroscopy, cylindrical-coordinates, local-measurement
toroidal_angle_of_line_of_sight_second_point_from_spectrometer¶
Toroidal angle (φ coordinate) of the second point defining the spectrometer line of sight.
Toroidal angle coordinate φ of the second endpoint of the spectrometer diagnostic line of sight. Convention: φ oriented counter-clockwise when viewing from above. For tangential views, the difference between first and second point toroidal angles determines the viewing geometry relative to magnetic field lines.
Unit: rad
Status: Draft
Tags: spectroscopy, cylindrical-coordinates, local-measurement
vertical_position_of_line_of_sight_first_point_from_spectrometer¶
Height (Z coordinate) of the first point defining the spectrometer line of sight.
Vertical coordinate (height Z) of the first endpoint of the spectrometer diagnostic line of sight in cylindrical coordinates (R, φ, Z). Z is measured vertically along the tokamak symmetry axis, typically with Z = 0 at the machine midplane. Positive Z is upward direction. This coordinate, together with R and φ, defines the 3D starting position of the diagnostic viewing chord.
Unit: m
Status: Draft
Tags: spectroscopy, cylindrical-coordinates, local-measurement
vertical_position_of_line_of_sight_second_point_from_spectrometer¶
Height (Z coordinate) of the second point defining the spectrometer line of sight.
Vertical coordinate (height Z) of the second endpoint of the spectrometer diagnostic line of sight. Together with the first point coordinates, defines the complete 3D geometry of the diagnostic viewing chord through the plasma. The chord path determines which plasma regions contribute to the measured spectral signals.
Unit: m
Status: Draft
Tags: spectroscopy, cylindrical-coordinates, local-measurement
wavelength_from_spectrometer¶
Wavelength coordinate for spectroscopic measurements in the visible light range.
Wavelength coordinate array for grating spectrometer measurements in the visible light range (typically 380-750 nm). Each element corresponds to a wavelength pixel or channel of the detector. Wavelength calibration is typically performed using known spectral lines from plasma impurities or external sources. The wavelength resolution depends on the grating groove density and detector pixel size.
Unit: m
Status: Draft
Tags: spectroscopy, measured