scpn-control is a control research layer for tokamak plasma scenarios. It processes diagnostic inputs, computes stability and transport quantities, and evaluates candidate control actions behind fail-closed admission gates. It does not have live tokamak actuator authority.
- Strict Fallback Degradation: Compute dispatch attempts
scpn-control-rs(Rust) first, falls back tosc-neurocore(JAX/GPU acceleration) where available, and finally to strictly typed pure NumPy/Python. A missing native backend degrades the compute path; it does not crash the loop. - Control-Loop Latency: Measured latency artefacts (per-kernel and end-to-end percentiles, with recorded host, affinity, and isolation context) live in
validation/reports/and are regression-gated in CI. All committed figures carry an evidence class and are local-regression evidence, not facility or production timing claims; seeVALIDATION.mdfor the current claim boundary. - Stochastic Petri Nets (SPNs): Supervisory logic is expressed as SPNs executed via populations of Leaky Integrate-and-Fire (LIF) neurons, providing graceful behaviour under diagnostic noise and sensor dropouts.
The architecture is domain-configurable: the controller updates its AdaptiveKnmEngine, and layer adapters map domain telemetry onto the phase-coupling model.
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Plasma Control Loop: Uses
$\beta_N$ , Mirnov RMS, and Greenwald limits in research scenarios. Singular Value Decomposition (SVD) and$H_\infty$ control synthesis produce candidate magnetic coil voltage changes ($\Delta V_{coil}$ ) for Neoclassical Tearing Mode (NTM) suppression studies; these are not live actuator commands.
Three gyrokinetic transport paths are implemented:
- Path A — External GK Coupling: Interfaces to five first-principles codes (TGLF, GENE, GS2, CGYRO, QuaLiKiz) via subprocess with automatic input deck generation and output parsing; fail-closed when the external executable is absent. Transport solver mode:
transport_model="external_gk". - Path B — Native Linear GK Solver: Self-contained ballooning-space eigenvalue solver (Miller geometry, Sugama collision operator, Gauss-Legendre velocity grid), benchmarked against Cyclone Base Case reference ranges (Dimits et al. 2000). Quantitative cross-code agreement with external GK codes is an open validation target; see
VALIDATION.md. - Path C — Hybrid Surrogate+GK Validation: A QLKNN-style surrogate runs at microsecond speed; Mahalanobis + ensemble OOD detection triggers GK spot-checks, with a correction layer (multiplicative/additive/replace with EMA smoothing) and online retraining.
- SCPN Phase Bridge: An opt-in bridge maps GK growth rates and diffusivities onto the 8-layer UPDE Kuramoto coupling matrix (P0↔P1 microturbulence↔zonal flows, P1↔P4 zonal↔transport barrier, P3↔P4 sawtooth↔barrier). The bridge currently records coupling metadata; closed-loop actuation through the phase layer is a research lane, not a shipped control path.
- Nuclear Fusion (Digital Twin & Flight Sim): A full
tokamak_flight_sim.pyandtokamak_digital_twin.pyallow continuous integration testing of real-time control algorithms against a synthetic plasma model before any hardware exposure. - Industrial Control Research: The same SPN/phase-coupling architecture is applicable to nonlinear multi-actuator control problems (manufacturing, chemical reactors, grid balancing) as a research substrate; no production deployment in these domains is claimed.