VACUUM HEATING OF ELECTRONS AND ION-ACCELERATION IN ULTRASHORT LASER-PULSE INTERACTION WITH PLASMA

The results of analytical treatment and computer simulation of the interaction between the relativistically strong electromagnetic field of an ultrashort laser pulse and a highly inhomogeneous overdense plasma are presented. ''Vacuum heating of electrons:'' i.e., formation of a cloud of fast electrons that is expanding into vacuum is the primary mechanism responsible for electromagnetic energy absorption under the oblique incidence of an electromagnetic wave upon dense plasma with a sharp boundary. It is shown that, in the electron cloud expanding into vacuum, ions are accelerated up to the energies corresponding to the equality of ion and fast electron velocities