Normal-phase propagation over an HTSC film heated by microwave radiation

The dynamics of the S-N transition of a thin HTSC film heated by microwave radiation is studied theoretically. The dependence of the NS-interface propagation velocity v on the microwave power P is found by solving the non-stationary heat balance equation. Two-dimensional effects related to a non-linear heating over the thickness of a substrate, of which the reverse side is stabilized at a temperature T-0, are shown to be essential for calculations of the dependence v(P). A qualitative model which allows one to explain specific features of the NS-interface propagation is proposed. Analytical results are confirmed by a direct numerical simulation of the S-N transition process and differ appreciably from the prediction of the conventional one-dimensional theory. The results obtained may be of importance in the study of the S-N transition in superconducting microwave devices.