Current profiles and ac losses of a superconducting strip with an elliptic cross-section in a perpendicular magnetic field

We study the case of a hard type II superconductor in the form of a strip with an elliptic cross-section when it is placed in a transverse magnetic field. We approach the problem in two steps, both based on the critical-state model. First, we calculate numerically the penetrated current profiles that ensure complete shielding in the interior, without assuming an a priori form for the profiles. In the second step we introduce an analytical approximation that asumes that the current profiles are ellipses. Expressions linking the sample magnetization to the applied field are derived covering the whole range of applied fields. The theoretical predictions are tested by comparison with the experimental data for the imaginary part of ac susceptibility.