Tsvitkovskyi V. Mixed state electrodynamics in type-II superconductors with linear defects

The paper is devoted to solution of some problems related to the mixed state electrodynamics in type-II superconductors with columnar defects. A model of pinning and dynamics of Abrikosov vortices in superconductors of the second kind with linear columnar defects has been developed, taking into account the balance of forces acting on vortices from inhomogeneously distributed transport current, pinning force of linear defects and intrinsic vortex line tension under condition of a weak intervortex interaction. The stationary shape of the vortex line is calculated, which depends on the influence of external factors - the pinning force created by the linear defect, the transport current amplitude on the surface, and the vortex line elastic properties associated with the material anisotropy. The conditions for the appearance of instability of the vortex line pinned stateat given external conditions, which leads to the vortex escape from the columnar defect, are calculated. The density of the maximum transport current is calculated, which leads to the escape of the vortex from the defect - the depinning critical current density.