Theory of flux cutting and flux transport at the critical current of a type-II superconducting cylindrical wire
| Title | Theory of flux cutting and flux transport at the critical current of a type-II superconducting cylindrical wire |
| Publication Type | Journal Article |
| Year of Publication | 2011 |
| Authors | Clem JR |
| Journal Title | Physical Review B |
| Volume | 83 |
| Pages | 214511 |
| Date Published | 06/09 |
| ISBN Number | 1098-0121 |
| Accession Number | ISI:000291432700008 |
| Keywords | critical-state model, cylinder, force-free configurations, HARD SUPERCONDUCTORS, helical vortex instability, line, longitudinal magnetic-field, losses, surface, vortices |
| Abstract | I introduce a critical-state theory incorporating both flux cutting and flux transport to calculate the magnetic-field and current-density distributions inside a type-II superconducting cylinder at its critical current in a longitudinal applied magnetic field. The theory is an extension of the elliptic critical-state model introduced by Romero-Salazar and Perez-Rodriguez. The vortex dynamics depend in detail on two nonlinear effective resistivities for flux cutting (rho(parallel to)) and flux flow (rho(perpendicular to)), and their ratio r = rho(parallel to)/rho(perpendicular to). When r < 1, the low relative efficiency of flux cutting in reducing the magnitude of the internal magnetic-flux density leads to a paramagnetic longitudinal magnetic moment. As a model for understanding the experimentally observed interrelationship between the critical currents for flux cutting and depinning, I calculate the forces on a helical vortex arc stretched between two pinning centers when the vortex is subjected to a current density of arbitrary angle phi. Simultaneous initiation of flux cutting and flux transport occurs at the critical current density J(c)(phi) that makes the vortex arc unstable. |
| URL | <Go to ISI>://000291432700008 |
| DOI | 10.1103/PhysRevB.83.214511 |
| Alternate Journal | Phys Rev BPhys Rev B |
