MODELING OF BREAKDOWN OF A GAS BY ELECTRONS OF THE BOUNDARY-LAYER DURING IRRADIATION OF METAL TARGETS BY PICOSECOND LASER-PULSES

Results are presented from a numerical simulation of the breakdown of a dense inert gas by boundary-layer electrons upon irradiation of a me tal target by high-power picosecond laser pulses. It is shown that tak ing the electric field of the boundary layer into account leads to a s ubstantial increase in the concentration of the seed electrons near th e target surface, which accelerates the ionization process. The depend ence of the breakdown time on the electric field intensity of the inci dent wave and the concentration of the gas atoms is derived. (C) 1998 American Institute of Physics. [S1063-7842(98)00808-3].