1. Iron saturation now in the dynamics (was the "13 Tesla" bug). Flux
linkage lambda(x,I) = L_air*I + L_iron*overlap(x)*g(I) with
g(I)=I_sat*tanh(I/I_sat) saturating at the current where iron reaches
B_sat. Both the circuit back-EMF (dlambda/dx) and the force (coenergy,
dW'/dx) derive from the SAME lambda, so energy stays conserved (0.025%
error) AND the field caps at B_sat instead of running to 13 T. Reduces
to the old 0.5*I^2*dL/dx in the low-current limit. On the config that
reported 60% efficiency / 11.6 T, it now gives 40% / 1.90 T.
2. Switch surge-current limit is now a hard feasibility constraint: a
config whose peak discharge current exceeds the switch's pulse rating
(continuous * surge factor per device kind) is infeasible -- otherwise
the optimizer "wins" with configs that vaporize their own thyristor
(e.g. 119 A through a 12 A BT151). Capacitor current stays a warning
(electrolytics tolerate pulses; DB has continuous not pulse ratings).
Regression tests added for both (field cap near saturation, energy
conservation under strong discharge). 87 tests pass.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
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