Thermal mechanism of microwave breakdown in HTSC films: theoretical arguments and experimental evidence

Theoretical arguments for the thermal mechanism of HTSC him microwave break down and their consequences are compared with experimental data. The measur ed values of the microwave breakdown surface magnetic field are shown to ob ey the temperature dependence corresponding to the thermal mechanism. The s pace-time pattern of the microwave breakdown seems to be related to a local overheating of the film in the vicinity of defects of size 1-10 mu m. The further increase of the breakdown field may be restricted by a sharp decrea se of the critical energy of external thermal disturbances initiating the m icrowave breakdown.