Burner Plug Safety
The tandem-mirror plugs confine plasma with high field; if plug performance drops, the plasma leaks out and the burn ends — a safe direction.
The burner (Aegis / MetroVolt) is a tandem-mirror machine: plasma is confined along a central cell and plugged at each end by regions of very high magnetic field — 26.49 T at the plugs, 17 T at the throat. These plugs are the confinement, and their failure mode is inherently safe: weaken a plug and particles simply escape, ending the burn.
The safe failure direction
- Plug field drop → confinement drops → plasma leaks out the ends → burn stops.
- No mechanism converts plug loss into more fusion — the reaction only declines.
- End losses are directed into the direct-energy-conversion and dump regions by design.
- Loss of plug power or magnet current terminates confinement.
The mirror architecture makes the burn contingent on continuously maintaining the plug fields. There is no stable high-burn state that persists if the plugs falter; the machine must hold the plugs to hold the plasma. This is the burner's version of the burn fragility that guarantees the reaction cannot run away.
Coupled hazards handled separately
The 26.49 T plug field is the burner's highest magnet hazard, so its stored energy, quench protection, and cryogenics receive focused design attention — see stored magnetic energy. But a plug magnet fault ends confinement first and foremost, terminating the reaction while the magnet-protection systems manage the electromagnetic energy.
The burner's low 5.44% neutron fraction means even sustained operation activates little material, keeping its overall radiological footprint light.