PENETRATION OF CIRCULARLY-POLARIZED ELECTROMAGNETIC-FIELDS INTO SUPERCONDUCTORS WITH GRADUAL RESISTIVE TRANSITIONS

Critical state-type models of superconducting hysteresis are based on analytical study of penetration of electromagnetic fields into hard superconductors. This study has been carried out under the assumption of ideal (sharp) resistive transition. In the paper, the attempt is made to study the penetration of electromagnetic fields into hard superconductors for gradual resistive transitions described by the ''power law.'' This requires the solution of nonlinear partial differential equations. It is shown that the exact analytical solution can be found in the case of circular polarization of electromagnetic fields due to the high degree of symmetry of the posed problem. In the limiting case of sharp transition, the obtained solutions are reduced to the solution previously asserted by Bean.