Two plasmon decay, ion acoustic waves, and the (3/2)/spl omegasub o/-thermometer in laser produced plasmas

Summary form only given. In order to investigate the relation between TPD and (3/2)/spl omegasub o/-radiation the authors have conducted an extensive experimental survey of the growth and saturation of TPD waves in a CO/sub 2/-laser-irradiated long-scale-length plasma of /spl sim/quarter critical maximum density. Using ps-streak camera detection of visible Thomson-scattered probe laser radiation the wave vector distribution of TPD waves in the complete k/sub x/ (/spl par/ k/sub o/), k/sub y/ (/spl par/ E/sub o/) plane as well as the amplitude of ion waves has been measured. The (3/2)/spl omegasub o/-emission into various angles has been spectrally analyzed at the same time. The results show a close correlation between the saturated TPD wave amplitudes at the k/sub x/, k/sub y/ locus for scattering of /spl omegasub o/-radiation and the (3/2)/spl omegasub o/-emission into the corresponding angle. In the k-half plane with k/sub x/ > 0 the TPD growth proceeds mostly as predicted by linear theory. In the half plane with k/sub x/ < 0, however, the wave vector distribution is strongly modified from that expected theoretically. This modification can be associated with coupling to measured ion acoustic waves.