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

The results of analytical treatment and computer simulation of the int eraction 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 c loud of fast electrons that is expanding into vacuum is the primary me chanism responsible for electromagnetic energy absorption under the ob lique incidence of an electromagnetic wave upon dense plasma with a sh arp boundary. It is shown that, in the electron cloud expanding into v acuum, ions are accelerated up to the energies corresponding to the eq uality of ion and fast electron velocities.