LASER-BERNSTEIN-MODE COUPLING IN A LASER-PRODUCED PLASMA

Laser radiation propagating in a laser-produced plasma, in the presenc e of a self-generated magnetic field B-S can decay into an electron Be rnstein wave and a sideband Langmuir wave. Near the critical density, the laser may be linearly mode converted into a Langmuir wave, which m ay parametrically excite an electron Bernstein wave and a Langmuir wav e. Inhomogeneity in the B-S field determines the convective threshold for resonant and quasimode decay processes. In a plasma with electron temperature T-e similar to 0.5 keV and a B-S field scale length of sim ilar to 100 mu m the power threshold at a 1-mu m wavelength turns out to be 10(15) W/cm(2). Above the threshold the growth rate is of the or der of 3 x 10(11) s(-1) for a resonant decay and 10(11) s(-1) for a no nresonant quasimode decay.