Spheromak
A simply connected compact toroid whose toroidal and poloidal fields are both generated by internal plasma currents near a Taylor minimum-energy relaxed state, with no central column and no toroidal-field circuit linking the plasma. SCPN-SPHEROMAK-CORE owns the device truth of the spheromak configuration.
What the configuration is
Take a reversed-field pinch, remove the toroidal-field coils and the vessel's central hole, and let the plasma make both field components itself inside a conducting flux conserver: that is a spheromak. It is formed and sustained by a magnetised coaxial gun that injects magnetic helicity, and its lowest-energy state is fixed by the conserver's shape alone, which is why one number — the Taylor eigenvalue of the conserver — organises the device. Tilt and shift stability boundaries are set by the same conserver.
What the core owns
- the analytic device physics models: closed-form and 0-D models from the spheromak literature evaluated on the validated configuration; the Bessel and unit-circle kernels are the shared kernel library's, pinned here, not owned here;
- the device geometry and its 3D models: the gun-driven mechanical envelope (flux-conserver wall, coaxial gun electrodes, end wall) with deterministic analytic-surface and B-rep models and open-format exports, no engineering property carried;
- the device boundary: plant and experiment truth, shot lifecycle and configuration policy; formation and sustainment semantics by magnetised coaxial-gun helicity injection, including helicity-balance accounting at device level;
- the declared configuration: flux-conserver radius and length; gun current and bias flux as the formation source; whether external toroidal-field coils exist;
- diagnostic semantics, reference frames and clock identity declarations; actuator-response model boundaries and the safety envelope (including tilt/shift stability boundaries set by the conserver); the CONTROL adapter specification; the registry binding (version 1.0.0) and the domain manifest.
What it explicitly excludes
- Reversed-field pinch (external toroidal-field circuit, toroidal vessel): SCPN-RFP-CORE; field-reversed configuration (negligible toroidal field): SCPN-FRC-CORE, with the pulsed merge-compression workflow in SCPN-MIF-CORE; axisymmetric tokamaks: SCPN-TOKAMAK-CORE.
- Solver mathematics and validation evidence: SCPN-Fusion-Core, the canonical owner of shared solver surfaces, until an exact surface passes the reactor family migration gate; no solver code exists in, or was copied into, the device core.
- Typed signal semantics and comparability: SCPN-Phase-Orchestrator (review-only output, never actuation).
- Control admission and action formation: SCPN-Control is the sole software authority that forms an admitted control action.
- Machine protection: independent systems retain the final veto. Portfolio presentation, identity, entitlement and execution gating: SCPN-Studio.
Level-0 physics and its anchor
The Taylor eigenvalue of a right circular flux conserver, \(\lambda_{\mathrm{fc}} = \sqrt{(j_{1,1}/R)^2 + (\pi/L)^2}\) (Hooper 2003 definition, Wood 2005 value, PPPL-2257 scaling); the lowest axisymmetric relaxed-state field in the separation form, checked to be divergence-free and to satisfy \(\nabla\times\mathbf{B} = \lambda\mathbf{B}\) component by component by central differences, vanishing at the wall and the end plates; and the formation disposition of Wood 2005 from \(\lambda_{\mathrm{gun}} = \mu_0 I_{\mathrm{gun}}/\psi_{\mathrm{gun}}\) against \(\lambda_{\mathrm{fc}}\). A Rust crate mirrors every kernel; 560 field samples are compared bit for bit.
Anchored on one printed number: the SSPX conserver, 1 m in diameter by 0.5 m high, gives \(\lambda_{\mathrm{fc}} = 9.91\ \mathrm{m^{-1}}\) against the printed 9.9 within the declared one per cent (measured 0.1 %); doubling both extents halves the eigenvalue and both wavenumbers exactly. The cylindrical eigenvalue's own citation (Turner et al. 1983) is not on file; the separation form is derived in the repository and the curl identity is tested numerically.
Load the SSPX conserver in the explorer →
Non-claims
- Every number is a closed-form evaluation of the lowest axisymmetric relaxed state of an ideal cylindrical flux conserver on a synthetic configuration; no equilibrium reconstruction, stability, helicity balance or resistive decay is computed.
- The SSPX anchor reproduces one printed number within a declared tolerance; it is not a correlation with the machine's data.
- The magnetic axis, the helicity–energy relation, the tilt criterion and the decay time are not evaluated (no filed source or kernel).
- The formation disposition restates a published operating rule against a declared tolerance; it predicts nothing about any discharge.
- No value describes, approximates or validates any real machine; formation-source and fuel-cycle choices are configuration facets, not separate claims.
Capabilities and evidence
Evidence maturity computational_prototype, five implemented capabilities, each with its evidence record in VALIDATION.md: the device configuration model (validated parameter objects with documented consistency estimates, canonical serialisation, a data-only SPO registry pin); the diagnostic and clock semantics model (synthetic channel and clock declarations aligned fail-closed with the pinned SPO observability catalogue, typed frames, clock topology, signal inventories); level-0 device physics (the relaxed state, eigenvalue and formation disposition on this page, with native parity and a benchmark); the device 3D model and the device CAD model (tessellated on the shared kernel library and built again as exact solids). No parameter set or channel describes any real machine or diagnostic; the claim inventory is empty and verified by the domain validator.