Excitation and decay of low-lying nuclear states in a dense plasma produced by a subpicosecond laser pulse

The excitation of low-lying nuclear levels in a hot, dense plasma, produced by a subpicosecond pulse with intensity exceeding 10(16) W/cm(2), is investigated theoretically and experimentally. The basic channels of electronic (inelastic scattering and inverse internal electron convergence) and photon (photoexcitation) excitations of such states as well as the influence of the broadening of a nuclear level on the excitation efficiency and the presence of hot electronic component are examined. The experimental data from measurements of the decay kinetics of the low-lying nuclear level 6.238 keV of the stable isotope Ta-181, which were obtained on two experimental laser systems, are presented. (C) 2000 MAIK "Nauka/Interperiodica".