HELICAL INSTABILITY OF A MAGNETIC-FLUX LINE IN A CURRENT-CARRYING SUPERCONDUCTING FILM

An exact solution for helical magnetic vortex structure in a type-II s uperconductor strip subjected to a magnetic field parallel to a transp ort current is obtained. A field-dependent characteristic current of f lux-line instability with respect to helical distortions is found to b e comparable to experimental values of the critical current of dissipa tion onset in thin films. A resistive picture following from the above results includes a regime of magnetic moment and voltage oscillations that may be controlled by the current, field, and sample dimensions.