INCREASE IN THE TEMPERATURE OF A LASER-PLASMA FORMED BY 2-FREQUENCY UV-IR IRRADIATION OF METAL TARGETS

An experimental investigation was made of a laser plasma formed by suc cessive irradiation of a metal target with 30-ps UV and IR laser pulse s. The UV prepulse, of 266 nm wavelength, was of relatively low intens ity (similar to 10(12) W cm(-2)), whereas the intensity of an IR pulse , of 10.6 mu m wavelength, was considerably higher (similar to 3 x 10( 14) W cm(-2)) and it was delayed by 0-6 ns (the optimal delay was 2 ns ). Such two-frequency UV-IR irradiation produced a laser plasma with a n electron temperature 5 times higher than that of a plasma created by single-frequency IR pulses of the same (similar to 3 x 10(14) W cm(-2 )) intensity.