Gate: Plug Coil Overstressed 3-3.9x
At the design bore, the burner's high-field plug coil is overstressed by roughly 3 to 3.9 times, making it infeasible as specified without a materials or geometry change.
The finding
The tandem mirror needs a very high plug field — 26.49 T — produced by a compact plug coil. At the studied bore, the mechanical stress in that coil exceeds what the conductor and structure can bear by a factor of roughly 3 to 3.9. As specified, the plug coil is infeasible: it would fail structurally.
Why the field is so demanding
High plug fields are what make the tandem-mirror confinement work at all; the physics wants a large field, and a large field in a small bore concentrates enormous magnetic pressure in the coil structure. The stress scales steeply, so modest field increases become severe structural problems.
Paths under study (not solutions yet)
- Higher-strength or differently reinforced conductor and structure.
- Revised coil geometry and bore that trade field profile against stress.
- Materials advances validated by 14 MeV neutron irradiation testing from the breeder.
This is the first and most concrete gate: a specific, quantified structural overstress. It is stated as a physics-and-engineering fact. Until a coil design carries 26.49 T within allowable stress, the burner is not buildable as specified, and no downstream capability claim can stand ahead of it.
The most concrete of the four gates
Unlike a diffuse uncertainty, the plug-coil overstress is a specific, quantified structural result: roughly 3 to 3.9 times the allowable stress at the design bore. It is falsifiable and it is a hard stop — a coil cannot carry a load it fails under. Every downstream capability claim for the burner is subordinate to a coil design that carries 26.49 T within allowable stress.