The midplanes use the selected height and the side of the magnetic axis. The separatrix intersection is defined from that midplane, while dr_dz_zero_point retains its derivative-selected geometry. The other definitions keep their physical meaning and sibling pointers.
| Locus | Before | After |
|---|---|---|
inboard_midplane | High-field-side (inboard) equatorial midplane - the inner-midplane counterpart of outboard_midplane. The inner-midplane reference is the inboard intersection of the horizontal plane through the magnetic axis (or the DD midplane_identifier) with the plasma boundary / first wall. DD: e.g. equilibrium/time_slice/profiles_1d/r_inboard (inboard major radius of the flux surface at the midplane). | The high-field-side equatorial midplane: points at the midplane height with major radius less than the magnetic-axis radius. The data's midplane identifier selects that height, or it is the magnetic-axis height when none is given. |
limiter | Plasma-facing limiter. As a measurement locus, 'at_limiter' denotes the scrape-off-layer plasma immediately adjacent to the limiter surface; the DD provides only the limiter surface geometry (wall/description_2d/limiter) and the precise plasma evaluation point is not yet standardised (IMAS_3226). For the separatrix-limiter tangency CONTACT point use active_limiter_point; for a quantity distributed OVER the limiter surface (e.g. a peak power density) use the 'along' relation (along_limiter). | A plasma-facing limiter. At the limiter, a measurement refers to the scrape-off-layer plasma immediately adjacent to its surface; the precise plasma evaluation point is not specified. For the separatrix-limiter contact point use active_limiter_point; for a quantity distributed along the limiter surface use along_limiter. |
outboard_midplane | Low-field-side (outboard) equatorial midplane. The outer-midplane reference follows the DD midplane_identifier (default option 'dr_dz_zero_sep': the outboard separatrix point where dr/dz = 0). For a value at the separatrix intersection use outboard_midplane_separatrix. | The low-field-side equatorial midplane: points at the midplane height with major radius greater than the magnetic-axis radius. The data's midplane identifier selects that height, or it is the magnetic-axis height when none is given. For a value at the separatrix intersection use outboard_midplane_separatrix. |
outboard_midplane_separatrix | Intersection of the separatrix with the outboard (low-field-side) midplane - the outboard separatrix point where dr/dz = 0 (the local major-radius maximum of the separatrix). This is where a separatrix POINT value is evaluated. DD: equilibrium/time_slice/boundary_separatrix/dr_dz_zero_point; outer-midplane reference per the midplane_identifier. | The point where the separatrix crosses the midplane height on the low-field side, at a major radius greater than the magnetic-axis radius. The data's midplane identifier selects that height, or it is the magnetic-axis height when none is given. A separatrix point value at the outboard midplane is evaluated here. |
pedestal | H-mode edge transport-barrier (pedestal) region. Ambiguous as a single point: for a profile VALUE use pedestal_top; for a maximum-gradient or fit POSITION use pedestal_maximum. Prefer the more specific token over this bare one. DD: summary/local/pedestal, summary/pedestal_fits/*. | H-mode edge transport-barrier (pedestal) region. Ambiguous as a single point: for a profile value use pedestal_top; for a maximum-gradient or fit position use pedestal_maximum. Prefer the more specific token over this bare one. |
pedestal_maximum | Location of the maximum pedestal gradient (the steep mid-pedestal), i.e. the peak-gradient / fit position of the edge barrier. Distinct from the pedestal top. DD: summary/pedestal_fits/*/d_dpsi_norm_max_position, summary/local/pedestal/position/psi. | Location of the maximum pedestal gradient (the steep mid-pedestal), i.e. the peak-gradient / fit position of the edge barrier. Distinct from the pedestal top. |
pedestal_top | Top of the H-mode edge pedestal (the barrier's inner shoulder), where 'the pedestal value' of a profile is conventionally reported. DD: summary/pedestal_fits/* pedestal-top fit outputs. | Top of the H-mode edge pedestal (the barrier's inner shoulder), where the pedestal value of a profile is conventionally reported. |
separatrix | The flux surface through the primary X-point, where the poloidal flux equals its X-point value; it bounds the confined plasma only in a diverted configuration. For a flux-surface-averaged quantity apply the flux_surface_averaged operator (DD summary/local/separatrix_average/*); for a bare point value at the outboard midplane use outboard_midplane_separatrix. DD: summary/local/separatrix/*, equilibrium/time_slice/boundary_separatrix. | The flux surface through the primary X-point, where the poloidal flux equals its X-point value; it bounds the confined plasma only in a diverted configuration. For a flux-surface-averaged quantity apply the flux_surface_averaged operator; for a bare point value at the outboard midplane use outboard_midplane_separatrix. |
active_limiter_point | The point where the last closed flux surface of a limited plasma is tangent to (makes contact with) the limiter surface - the separatrix-limiter tangency point. Distinct from the SOL-adjacent 'at_limiter' locus. DD: pulse_schedule/position_control/active_limiter_point. | The point where the last closed flux surface of a limited plasma is tangent to (makes contact with) the limiter surface - the separatrix-limiter tangency point. Distinct from at_limiter, the scrape-off-layer plasma immediately adjacent to the limiter. |
dr_dz_zero_point | Outboard point on the separatrix where dr/dz = 0 (the local maximum of the separatrix major radius) - the geometric outer-midplane reference selected by the DD midplane_identifier option 'dr_dz_zero_sep'. DD: equilibrium/time_slice/boundary_separatrix/dr_dz_zero_point. | The outboard separatrix point where dR/dZ = 0, at a local maximum of the separatrix major radius. |
Red controls. The untouched-registry test exited 1: its DD-reference failure names all ten rows above, including outboard_midplane and outboard_midplane_separatrix. A planted change that removes the outboard height default, removes the inboard axis-side relation, and restores derivative wording at the outboard separatrix intersection exited 1 with all three test cases failing. Logs: locus-old-text-red.log and locus-planted-red.log in the run directory.
Grammar gate. Base ab55103ab168cb6e433b22caffde2643bc5330d6: 1,275 passed, 32 skipped, no failures, EXIT=0. Head 88f9ae8f12b64750ce3ef6cd2033897e3444d888: 1,278 passed, 32 skipped, no failures, EXIT=0. There are zero added failures. Logs: grammar-base.log and grammar-head.log in the run directory.
Vocabulary question. outboard_midplane_separatrix and dr_dz_zero_point coincide when the selected midplane height is the separatrix outermost-point height. Whether both tokens should remain is for a later vocabulary ruling.