Quasi-static magnetic behaviour of a disc-shaped type II superconductor

The isothermal, quasi-static, magnetic behaviour. including the internal field and flux distribution profiles and the bulk magnetisation of reversible (i.e. pin-free) and irreversible disc-shaped type II superconductors, in perpendicular applied field, are obtained from a rigorous theoretical treatment which explicitly includes the constitutive B[H-rev] relation and the vortex pinning force dependence on induction B. The iterative numerical procedure to obtain the critical state is described and calculations an made for the magnetic behaviour in thr low-re (niobium) and in the high-T-c, high-kappa (BSCCO) systems with various vortex pinning models. Particular calculations are also made for comparison with experimental magnetisation data on pure (almost pin-free) single crystal niobium disc specimens and for the 'arrow-head' effect. and for the vortex-lattice 'melting' transition in a BSCCO disc-shaped single crystal. (C) 1997 Elsevier Science B.V.