Vortex penetration in the uniaxial anisotropic superconductor

We study an interaction of the single vortex line with planar surface of the film and bulk sample of the uniaxial anisotropic superconductor. An energy barrier develops near the surface due to the combined action of the repulsion between the vortex and the external field and the attraction between the vortex and the shielding currents. The barrier depends on the external field strength and the orientation of the field with respect to the anisotropy axis. We calculate a critical entry field for which the barrier disappears and the flux penetration sets in into the superconductor. (orig.)