The Plug-Coil Prototype Program
A staged magnet program to take the plug coil from a 3-to-3.9x overstress result to a demonstrated, field-bearing coil.
From coupon to coil
The plug coil is the machine's hardest structural requirement. The prototype program builds up in scale: material coupons, sub-scale windings, then a representative coil section tested to the modelled 26.49 T field and its associated stress.
What each stage answers
- Coupons: do the alloys and conductor meet the assumed strength and fatigue?
- Sub-scale: can the winding carry the current density with margin?
- Coil section: does a real geometry survive the modelled stress at field?
- Prototype: does the plug hold 26.49 T at the design bore?
The go/no-go for the test burner
A test burner around 2032 cannot be committed until a plug prototype demonstrates margin. This program is therefore on the critical path, and its results directly determine whether the plug-stress gate is closing.
This program sits on the critical path because the plug is the machine's single hardest structural requirement. A test burner cannot be committed until a prototype coil demonstrates margin at or near 26.49 T, so the prototype schedule effectively sets the earliest credible test-burner date. Progress here is the clearest single indicator of whether the plug-stress gate is genuinely closing.