ELECTRONIC INSTABILITY DURING VORTEX MOTION IN CUPRATE SUPERCONDUCTORS - REGIME OF LOW AND HIGH MAGNETIC-FIELDS

The critical velocity upsilon(phi)(*) associated with the electronic instability predicted by Larkin and Ovchinnikov displays a cross-over effect from magnetic-field independent behavior at high fields to the proportionality upsilon(phi)(*)similar to B--1/2 at low fields. This low-field behavior results from the fact that upsilon(phi)(*) multiplied with the inelastic quasiparticle scattering time tau(in) must reach at least the intervortex distance, thereby ensuring spatial homogeneity of the nonequilibrium quasiparticle distribution. At high magnetic fields the flux-flow instability becomes unobservable due to the onset of fluctuation effects contributing to the resistivity.