Plug Coil Stress Gate

As specified, the coil structure to hold 26.49 T over the plug bore is overstressed by roughly 3–3.9x; the plug is infeasible exactly as drawn.

This is one of the four honest gates on the burner (Aegis / MetroVolt), stated as a design-and-simulation finding. The plug demands 26.49 T over a plasma-relevant bore. Magnetic forces on a coil scale with the square of the field, and at 26.49 T the hoop and radial loads exceed what the specified conductor-and-structure package can carry by a factor of roughly 3 to 3.9.

Put plainly: the plug coil as currently specified would be overstressed. It is not a marginal exceedance to be trimmed with a safety-factor argument; it is a multiple. The burner cannot be built to this drawing, and the design does not pretend otherwise.

What the gate does not mean

• It is a structural-mechanics finding, not an economic statement
• It does not imply the tandem-mirror concept is invalid
• It does not depend on a specific vendor or supplier
• It applies to the plug bore and field as currently specified

Paths that could close it

Closing the gate means changing the specification, the materials, or the geometry until the stress falls to feasible levels: higher-strength structural materials, graded or nested winding that redistributes load, a smaller bore, a lower plug field paired with a different confinement scheme, or stress-managed conductor architectures. Each path changes the machine and must be re-simulated. None is demonstrated today.

Stating this gate at full candor is deliberate. A burner design that hid a 3–3.9x structural overstress would not be trustworthy. The number is reported so the engineering problem is visible and specific.