REGRESSION - IMPROVEMENT - Disambiguate the Δ' variants; pin SLAYER inner-layer outputs

Three distinct Δ' quantities exist and their labels no longer distinguish them poorly:

- "Δ′ STRIDE-like BVP (PEST3)" — SingularSurfaces/Delta_prime_matrix from the riccati
  fundamental-matrix BVP; the tearing-stability Δ'. Pinned at source (riccati case) and
  now also as ingested by SLAYER, so a change in what SLAYER consumes is caught even
  when the source case is not run.
- "Δ′ Galerkin RDCON (PEST3)" — the resistive-DCON Galerkin outer solution. Both outer
  solvers are arranged in the PEST3 convention; the labels now say so explicitly.
- "PE driven-response Δ′ (SingularCoupling jump)" — the forced ∂b^ψ/∂ψ jump over 2π·χ₁
  under applied flux: a driven-response diagnostic, not a tearing-stability Δ', and the
  case comment now says so.

The per-surface ca-based Δ' (compute_delta_prime_from_ca!) is a stub — documented as
not physically valid, never written to gpec.h5 — and is deliberately not pinned.

The SLAYER case also gains the inner-layer solve's own per-surface outputs: complex
layer thickness δ_s, δ_s/d_β, |δ_s| [m], and d_β [m]. The adaptive-scan Δ(Q) sample
arrays are deliberately NOT pinned: AMR sample locations move under any refinement
change, so they have no stable identity. Validated end-to-end: 21 quantities extract
on the DIII-D SLAYER deck.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: d-burg

regression-harness/cases/diiid_n1_riccati.toml

@@ -16,15 +16,15 @@ example_dir = "examples/DIIID-like_riccati_deltaprime_example"
 h5path = "SingularSurfaces/Delta_prime_matrix"
 type = "complex_matrix"
 extract = "diagonal_complex"
-label = "delta prime (BVP diagonal)"
+label = "Δ′ STRIDE-like BVP (PEST3) diagonal"
 noise_threshold = 1e-8
 order = 10
 
 [quantities.delta_prime_raw]
 h5path = "SingularSurfaces/Delta_prime_raw"
 type = "complex_matrix"
 extract = "all_complex"
-label = "delta prime (raw side-major)"
+label = "Δ′ STRIDE-like BVP (PEST3) raw side-major"
 noise_threshold = 1e-8
 order = 11
 

regression-harness/cases/diiid_slayer_n1.toml

@@ -132,6 +132,52 @@ label = "SLAYER no_root flags [2/1,3/1,4/1]"
 noise_threshold = 0
 order = 34
 
+# Outer-region Δ' consumed by the SLAYER matching — the same STRIDE-like BVP (PEST3) matrix
+# the riccati case pins at source; tracked here too so a change in what SLAYER actually
+# ingests is caught even if the source case is not run.
+[quantities.slayer_delta_prime_diag]
+h5path = "Tearing/PerSurface/Delta_prime_matrix"
+type = "complex_matrix"
+extract = "diagonal_complex"
+label = "Δ′ STRIDE-like BVP (PEST3) diagonal, as ingested by SLAYER"
+noise_threshold = 1e-8
+order = 40
+
+# Inner-layer solve outputs per surface (the resistive-layer Riccati solution itself, not the
+# outer matching). The adaptive-scan Δ(Q) sample arrays are deliberately NOT pinned: AMR sample
+# locations move under any refinement change, so they have no stable identity to pin.
+[quantities.slayer_delta_s]
+h5path = "Tearing/LayerWidths/delta_s"
+type = "complex_vector"
+extract = "all_complex"
+label = "SLAYER inner-layer thickness δ_s (complex, Riccati)"
+noise_threshold = 1e-10
+order = 41
+
+[quantities.slayer_delta_s_over_d_beta]
+h5path = "Tearing/LayerWidths/delta_s_over_d_beta"
+type = "complex_vector"
+extract = "all_complex"
+label = "SLAYER inner-layer δ_s/d_β (complex, dimensionless)"
+noise_threshold = 1e-10
+order = 42
+
+[quantities.slayer_delta_s_abs]
+h5path = "Tearing/LayerWidths/delta_s_abs"
+type = "real_vector"
+extract = "all_real"
+label = "SLAYER inner-layer physical thickness |δ_s| [m]"
+noise_threshold = 1e-12
+order = 43
+
+[quantities.slayer_d_beta]
+h5path = "Tearing/LayerWidths/d_beta"
+type = "real_vector"
+extract = "all_real"
+label = "SLAYER β-weighted ion drift scale d_β [m]"
+noise_threshold = 1e-12
+order = 44
+
 # Settings (catches accidental config drift)
 [quantities.slayer_enabled]
 h5path = "Tearing/enabled"

regression-harness/cases/gal_resistive_diiid.toml

@@ -31,7 +31,7 @@ order = 11
 h5path = "SingularSurfaces/GalerkinDeltaPrime/pest3_Delta"
 type = "complex_matrix"
 extract = "diagonal_complex"
-label = "gal PEST3 Δ diagonal"
+label = "Δ′ Galerkin RDCON (PEST3) diagonal"
 noise_threshold = 1e-6
 order = 20
 
@@ -40,7 +40,7 @@ order = 20
 h5path = "SingularSurfaces/GalerkinDeltaPrime/Delta_prime_raw"
 type = "complex_matrix"
 extract = "norm"
-label = "||gal Δ′ matrix||"
+label = "||Δ′ Galerkin RDCON (PEST3) matrix||"
 noise_threshold = 1e-6
 order = 21
 

regression-harness/cases/gal_resistive_pe.toml

@@ -66,12 +66,14 @@ label = "penetrated b field"
 noise_threshold = 1e-8
 order = 32
 
-# Per-surface Δ' from the PE singular-coupling analysis
+# Per-surface driven-response Δ' from the PE singular-coupling jump (∂b^ψ/∂ψ across the
+# rational surface over 2π·χ₁, forced by the applied flux). This is a driven-response
+# diagnostic, NOT the tearing-stability Δ' of the STRIDE-like BVP or Galerkin RDCON solvers.
 [quantities.pe_delta_prime]
 h5path = "PerturbedEquilibrium/SingularCoupling/Delta_prime"
 type = "complex_vector"
 extract = "all_complex"
-label = "PE Δ' per surface"
+label = "PE driven-response Δ′ (SingularCoupling jump)"
 noise_threshold = 1e-8
 order = 33