Experimental evidence for various mechanisms for suprathermal electron generation in P-polarized laser produced plasmas

The angular dependence of the absorbed laser energy which appears in suprathermal electrons and their temperature have been studied in P-polarisation, in laser produced plasmas. We have used two laser wavelengths 10.6 μm and 0.53 μm at irradiances of 10 12 and 10 14 W/cm 2 respectively, focused on plane mylar targets. The results show that in addition to resonant absorption fast electrons are generated (at an incidence angle of the laser beam of 60°) by another mechanism. The results are consistent with the latter, that is, with two plasmon decay instability La dependance angulaire de l'energie laser absorbee dans les interactions laser-plasma par les electrons suprathermiques a ete etudiee en polarisation P. Deux longueurs d'onde sont utilisees, 10,6 μm et 0,53 μm, avec des eclairements respectifs de 10 12 et 10 14 W/cm 2 sur des cibles de texphane. En dehors de l'absorption resonnante, un mecanisme cree des electrons rapides. Les resultats sont compatibles avec un declenchement de l'instabilite de decomposition en deux ondes de plasma