Subpicosecond 41.8-nm X-ray laser in the plasma produced by femtosecond laser irradiation of a xenon cluster jet

Model calculations are performed of the radiation gain for the 4d5d (J = 0) – 4d5p (J = 1) transition with a wavelength of 41.8 nm in Pd-like xenon ions in the plasma produced by femtosecond laser irradiation of a xenon cluster jet. Conditions for the excitation of an ultrashort-pulse (~1 ps) X-ray laser are discussed.