The Plug-Density Open Item

The central open physics question is whether the tandem-mirror plug confines the plasma at a feasible operating point — unresolved today.

The question

A tandem-mirror generator confines plasma between two high-field magnetic plugs. MetroVolt’s design uses a 26.49 T plug and a 17 T throat. The core open item is whether the plug provides adequate confinement — sufficient plug density and potential to hold the central-cell plasma — at a plasma pressure (β) that is actually feasible to build and sustain.

This is the single most consequential gate for the burner. If the plug requires conditions beyond what the magnets and heating can deliver, the design point changes. We flag this as genuinely open: it is not resolved by the current simulation, and it is a candidate to revise the concept.

How it gets resolved

Simulation narrows the plausible range but cannot settle it. The ~2032 test unit is the instrument: it measures confinement directly at the burner’s scale. A pass confirms the operating point; a shortfall sends the design back with concrete data.