ANULUM / SCPN Reactor Systems / Magneto-inertial and magnetised-target systems / Glossary

Glossary

The vocabulary of this family, defined the way the family's own repositories and the SCPN Reactor Family Repository Standard use it.

Magneto-inertial fusion (MIF): Compression of a pre-magnetised target on inertial time-scales; the embedded field slows thermal conduction out of the fuel while a driver does the compressing. Also called magnetised target fusion (MTF).
Magnetised target: The plasma that is compressed: fuel carrying an axial field (MagLIF), a plasma inside a material liner, or a compact toroid such as an FRC.
Liner: Whatever does the compressing by moving inward: a conducting metal shell driven by a current pulse (MagLIF), a solid pusher assembly or rotating liquid metal (material liner), or a shell formed by merging plasma jets. A liner is declared from the outside in: inner radius, wall thickness, length, material density.
Convergence ratio \(C\): \(r_0/r\), the initial radius over the radius at stagnation; strictly greater than one, or nothing is compressed.
Flux compression: Conservation of the axial magnetic flux \(B_z\pi r^2\) through a perfectly conducting liner, giving \(B = B_0 C^2\). An ideal limit: a real liner loses flux.
Adiabatic compression: Compression without heat exchange, \(T \propto n^{\gamma-1}\): \(T_0 C^{2(\gamma-1)}\) for a cylinder, \(T_0 C^{3(\gamma-1)}\) for a sphere. An ideal limit: a real compression radiates and conducts.
Adiabatic index \(\gamma\): The ratio of specific heats; 5/3 for a monatomic gas. Must exceed one, or the compression would not heat.
Magnetic pressure: \(B^2/2\mu_0\), the pressure a field exerts; used for the drive field at a liner surface and for the target's initial field.
Plasma beta: Thermal pressure over magnetic pressure. Under ideal cylindrical compression it falls as \(C^{-2/3}\). An FRC has average beta \(1 - x_s^2/2\), close to one.
Premagnetisation, preheat, implosion: The three MagLIF stages: an axial field put through the fuel by a coil pair; laser energy deposited in the fuel column; the pulsed-power drive of the liner.
Magneto-Rayleigh–Taylor (MRT) instability: Ripple growth at an accelerating liner–plasma interface, the limiting instability of liner implosions. The device cores carry it as a budget; the growth rate is implemented in SCPN-Fusion-Core.
Characteristic implosion time: \(r_0/v\), the time a shell needs to cross its own initial radius at the declared velocity; a scale, not a trajectory.
Standoff driver: A driver that stays at the chamber wall and is not destroyed by the shot, as plasma guns are; a precondition for repetition.
Cap sum: The fraction of a sphere that the spherical caps subtended by \(N\) jets add up to; a sum of areas, not a coverage map, because caps cannot tile a sphere.
Ram pressure: \(\rho v^2\), the pressure a moving fluid exerts when stopped.
Field-reversed configuration (FRC): A prolate compact toroid with no toroidal field, whose plasma current reverses the external axial field inside the separatrix.
Separatrix; \(x_s\); elongation \(E\): The surface dividing closed from open field lines in an FRC; its radius over the coil radius; its length over its diameter.
Kinetic-scale parameter \(S^*\): Separatrix radius over ion skin depth \(c/\omega_{pi}\). The empirical bound \(S^*/E < 3.5\) orders operating points; it does not claim stability.
Merge window: The condition SCPN-MIF-Core requires for two plasmoids at the chamber centre: phase separation below 0.01 rad and position within 2 mm of the reference for three consecutive samples.
Level-0 device physics: Closed-form evaluation of elementary relations on a declared operating point, recorded with non-claims and a SHA-256 digest; the lowest physics capability a device core implements.
Evidence maturity: One of six states per capability — architecture_only, computational_prototype, benchmark_validated, external_code_parity, experiment_correlated, control_research_ready. Repository age, code volume, simulation output or a controller's existence does not advance it; none of the states means machine-ready, safety-certified or reactor-ready.
Printed versus declared: A printed value is one a filed source prints and the core reproduces; a declared value is one the configuration carries because the source does not print it, and the record says so.
Upper bound: What an ideal conservation law gives: the value a real device cannot exceed, never the value it reaches.