Analysis Of Critical Power Loss In A Superconductor

A critical power dissipation resulting from an oscillating magnetic field, Hp cos wt, can produce a magnetic breakdown field, H <Hc, the critical field of the superconductor. The analysis shows, for example, why the breakdown field of a superconducting microwave cavity can be well below Hc in some cases, and indicates what the functional dependence of the cavity Q may be for values of Hp near H . The effective resistivity of a single isolated oscillating fluxoid, as well as that of a stationary normal region, is also derived for both type I and type Il superconductors.