THE ENERGY AND STABILITY OF A VORTEX LINE IN ANISOTROPIC LONDON THEORY

We show that the London theory expression for the energy of a system of vortex lines in anisotropic superconductors may be written in several different but equivalent forms because vortices form either closed loops or infinite lines. The divergence of the vortex lines' short distance interactions is handled by two procedures, the Gaussian and Pauli-Villars regularization methods. The stability of straight vortex lines perpendicular to the CuO2 planes in high-T(c) superconductors is investigated from the point of view of anisotropic London theory. We show that the straight line is always an equilibrium configuration and its stability depends on the properties of the vortex core. The self-energy of spiral vortex lines whose axes coincide with the axis of anisotropy is computed and compared to that of the straight line parallel to the axis of anisotropy.