Noncyclotronic Vortex Mode in Clean Type II Superconductors

Abstract
Various vortex modes in a superconducting slab are analyzed. In addition to the well known cyclotronic mode, whose frequency is generally proportional to the magnetic field, a noncyclotronic mode with a much lower frequency can be excited in the presence of a surface pinning. The frequency of this mode can decrease with the magnetic field, as observed in recent experiments.