Microwave discharge on a dielectric surface in vacuum

The paper describes the results of investigation of a discharge arising in vacuum on the surface of solid dielectric materials when irradiated by inte nse (up to 25 MW/cm(2)) electromagnetic centimeter wave radiation. When the density of the microwave energy flux exceeds some threshold value dependin g on the target material, a discharge emerges in the vicinity of the surfac e. Its emergence is associated with the evaporation of the target material and the breakdown of evaporated matter. The thus forming plasma initially h as the form of a thin (on the wavelength scale) layer with the electron den sity of the order of 10(16) cm(-3). It is demonstrated experimentally that effective generation of multiply charged ions occurs in the plasma. The mea sured energy distribution of ions in expanding plasma agrees with the predi cted distribution obtained in solving the problem on quasineutral expansion into vacuum of a localized bunch of collisionless plasma with cold ions. ( C) 2001 MAIK "Nauka/ Interperiodica".