Magnet Strain Deltas

The change in REBCO magnet strain against the ICE-PISTON preload baseline is a first-class feature guarding the highest-field components of both machines.

Strain as a health feature

The high-field REBCO magnets carry enormous electromagnetic loads — 16.84 T peak in the breeder, 26.49 T at the burner's plugs. Strain gauges bonded across the winding pack and structure report deformation; the engineered feature is the delta of that strain against the baseline set by the ICE-PISTON cryogenic preload cycle. A delta outside its envelope is an early warning of a mechanical or electromagnetic anomaly.

Baseline from the preload cycle

The ICE-PISTON preload establishes a known mechanical state before operation. The fabric records that state as the strain baseline. During a shot, the delta isolates the operational load from the static preload, so the feature responds to what the plasma and field are doing, not to the fixed clamp.

def strain_delta(strain_now, preload_baseline):
    # microstrain change attributable to operation
    return strain_now - preload_baseline

def within_envelope(delta, lo, hi):
    return lo <= delta <= hi   # per-gauge limits from structural model

From feature to failsafe

• A strain delta trending toward its limit is a quench precursor candidate for the anomaly ensembles.
• A hard limit breach is exactly the kind of event the L1 autonomous hardware failsafe can act on without AI in the loop.
• Strain deltas feed the twin's Thermomechanics module and the structural-health monitoring of the CrMoNbV vessel and carbon-fiber cocoon.

Both machines, same feature

Whether guarding the breeder's central column and toroidal set or the burner's 26.49 T plug coils, the strain-delta feature is defined identically; only the per-gauge envelopes, drawn from each machine's structural model, differ. These envelopes are versioned in the schema registry.