Theta-pinch — azimuthal current, axial field
A linear device in which a fast-rising axial field from a single-turn coil induces an azimuthal plasma current whose interaction with the axial field radially implodes and compresses the column. SCPN-THETA-PINCH-CORE owns the device truth of the theta_pinch configuration.
What the configuration is
Reverse the roles of the Z-pinch — current around the column, field along it — and the column is compressed by an external field it cannot tear apart the way a self-pinched column can. Theta-pinches of the 1960s and 70s reached kilovolt temperatures in microseconds by implosion heating followed by adiabatic compression; their weakness was the open ends, through which the plasma leaks on a time proportional to the coil length over the square root of the ion temperature. The Scyllac programme tried to close the ends by bending the coil into a torus and holding the plasma in place with helical and bumpy auxiliary fields; its 1973 review is the filed source of every relation the core evaluates.
What the core owns
- the analytic device physics models: closed-form and 0-D models from the theta-pinch literature evaluated on the validated configuration (no solver code, no FUSION seam);
- the device boundary: plant and experiment truth, shot lifecycle and configuration policy for linear devices driven by a single-turn compression coil; implosion-heating and adiabatic-compression semantics (shock formation, end-loss timescales of the open-ended geometry) as configuration facets;
- the declared configuration: coil field, coil radius and coil length; plasma pressure;
- diagnostic semantics, reference frames and clock identity declarations; the CONTROL adapter specification; the registry binding (version 1.0.0) and the domain manifest.
What it explicitly excludes
- Axial-current Z-pinch devices (current and field roles reversed): SCPN-Z-PINCH-CORE; dense plasma focus: SCPN-DENSE-PLASMA-FOCUS-CORE.
- FRC equilibrium, transport and stability physics: SCPN-FRC-CORE — theta-pinch-class programming appears there only as an FRC formation facet; this core owns the theta pinch as a compression device in its own right.
- Solver mathematics and validation evidence: SCPN-Fusion-Core, 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. Machine protection: independent systems retain the final veto. Portfolio presentation and gating: SCPN-Studio.
Level-0 physics and its anchor
The sharp-boundary state (\(\beta\), the equal-species temperature, the Alfvén speed and the end-to-centre propagation time); the Scyllac \(l = 1, 0\) toroidal equilibrium of eqs. 3 and 7 with the anchor at the 5-m sector point of Fig. 2 (\(\beta = 0.85\), \(a = 0.7\) cm, \(R = 2.375\) m, \(h = 0.19\) cm⁻¹: required product −0.0059 against measured −0.0064 and plotted ≈ −0.0065, 10 % tolerance); the \(m = 1\) growth estimate of eqs. 4 and 6 with the wall condition derived from eq. 6, reproducing the worked example \(a/b = 0.4\) to 0.399 and landing within a factor of two of the source's calculated 1.0 MHz for the 5-m sector; the end-loss scaling \(\tau \propto L/T_i^{1/2}\) normalised to the linear Scyllac point (5 m, 2.7 keV, 11.5 µs) and reproducing the Scylla IV-1 and IV-3 rows within 1 %. Source: Quinn et al., LA-UR-73-1053 (1973), OSTI 4460392, open access.
Load the Scyllac sector in the explorer →
Non-claims
- Every number is a closed-form evaluation of a 1973 sharp-boundary model on a synthetic configuration; no equilibrium, stability, compression or transport equation is solved.
- The anchors reproduce numbers printed in the source; they are not correlations with experimental data, and the growth-rate anchor is an order-of-magnitude reproduction by design.
- No adiabatic-compression, implosion-heating, yield, gain, reactivity or confinement statement is made; the end-loss scaling is an empirical three-device fit that the source itself contrasts with two disagreeing theoretical models.
- No value describes, approximates or validates any real machine; coil-geometry 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, the diagnostic and clock semantics model, level-0 device physics (the closed forms on this page, with a Rust crate mirroring every kernel in identical operation order, float64 bit patterns compared, and a per-point evaluation benchmark), the device 3D model and the device CAD model. No parameter set or channel describes any real machine or diagnostic.