Force free magnetic fields in a type II superconducting sphere

Publisher Website
Google Scholar
Abstract
Solutions for the magnetic flux configuration inside a current carrying Lorentz force free superconducting sphere are presented. Experiments have been conducted on a 0.95 cm diameter Pb-40 at % Tl sphere at 4.2K in which the sphere is subjected to a range of fields (0 to Hc2) and currents (0 to 1000 A) in a longitudinal configuration, to test its behaviour against the theoretical predictions. Axial magnetization is found to be in quite good agreement with the calculated values. Polar potential probes show, however, that a flux flow resistance occurs over a wide range of current and field values. An attempt to compress flux isotropically into the sphere so as to establish a final configuration in which there is no current across the sphere surfaces, but in which the field is stronger in the interior than that applied, has been unsuccessful. This inability to establish a metastable state has led to the conclusion that the order of application of field and current constraints has no influence on the final configurations achieved.

This publication has 7 references indexed in Scilit: