Generalized critical-state model of type II superconductors

Abstract

A modified form of the critical-state model of type II superconductors is described which takes account of Hc1 and surface sheath currents. The penetrating flux, hysteresis loop characteristics, a.c. losses and rate of penetration of flux into the superconductor when exposed to a sinusoidal magnetic field are evaluated. The model implies zero power dissipation for peak applied fields less than Hc1+ΔH and rapidly increasing dissipation just above this region, asymptotically approaching that derived from the Bean-London model.