Nonlinear Thermomagnetic Waves in Type II Superconductors

Abstract

This work is devoted to analysis of the nonlinear dynamics of interrelated thermal and electromagnetic perturbations in a superconductor caused by dissipative effects involved in the viscous motion of the magnetic flux. The structure and evolution of the stationary thermomagnetic waves propagating in the superconductor is studied based on a system of nonlinear equations describing dynamics of the instability development in the system studied. The apperance of these structures is qualititively described and the wave propagation velocity is estimated. The affect a thermoactivated flux creep to the structures of the nonlinear thermomagnetic wave propagation is studied. It is shown that taking into account a nonlinear dependency of the current density $j$ on the electric field strength $E$ would not qualitatively change the main results, since the character of the equilibrium state on the phase plane remains esentially the same.