The Plug-Density Gate
The burner's tandem-mirror confinement depends on an unproven plasma-density requirement at the plug.
How a tandem mirror confines plasma
A tandem mirror confines a central plasma between two high-field magnetic mirrors, or plugs, that create an electrostatic potential to hold ions. The burner (Aegis / MetroVolt) design specifies a 26.49 T plug and a 17 T throat. The concept's viability hinges on reaching and sustaining the plasma density the plugs require while preserving stability.
Why it is an open gate
- The required plug density at feasible magnetic field and plasma beta has not been demonstrated in this design.
- Tandem mirrors historically face MHD and micro-stability challenges; a demonstrated magnetic well at feasible beta is not yet in hand.
- D-3He demands higher performance than D-T, so the margin for confinement shortfalls is smaller.
- Without the plug, the downstream chain — burn and direct conversion — does not follow.
Stated as a requirement, not a result
Kronos flags a plug-density requirement as a caveat on the burner design point: the closing simulation reproduces on the deposited mirror, but it carries this requirement as a condition. Until the plug is shown to hold at feasible conditions, the burner is plug-gated, and no net-power claim is made for it. This is the single largest technical gate on the burner side.