Dynamics and drag of a vortex in type II superconductor with weak inhomogeneities

The dynamics of the Abrikosov vortex lattice and a single vortex in a type II superconductor with defects is studied taking into account inertial as w ell as gyroscopic (Hall) properties. The spectrum of normal modes in the ab sence of defects has two branches. In the limit of small k, one of the bran ches is gapless and has a quadratic dispersion relation, while the other br anch has a finite gap. In the limit of large k, the dispersion relations fo r both modes become linear (acoustic). It is shown that the interaction wit h defects in a moving vortex or a vortex lattice excites oscillations corre sponding to these modes. This creates an additional energy dissipation chan nel for translation motion of the vortex. In the case of a single vortex, t he corresponding drag force diverges as V-1/2 for V --> 0, i.e., prevails o ver the regular force of viscous friction for small velocities. (C) 1999 Am erican Institute of Physics. [S1063-777X(99)00411-9].