Flux spiral instability in a transport current carrying type II superconductor

The nucleation of vortex flux lines on a surface of a transport current carrying type II superconductor in the presence of an external magnetic field Hsub(e) occurs at Hsub(e) approx. = Hsub(c1), the first critical field. A spiral flux line in a long cylinder and in a long thin ellipsoid is investigated. In the latter case the force-free magnetic fields are also considered. (author)