The Admissible Operating Window - Which Constraints Actually Bind

The operating window synthesized from two findings: a strict invariance — source strength and wall loading trade one-for-one against centrepost life across the whole density–temperature plane, so there is no free operating-point gain — and a coupled admissible-current window whose floor is the q95/MHD edge and ceiling the centrepost fluence, with the tritium-startup requirement non-binding at ~1.7× margin.