UBC Theses and Dissertations
The production of hot electrons by the two-plasmon decay instability in a CO2 laser plasma interaction Legault, Lawrence E.
The generation of hot electrons characterizing the two-plasmon decay (TPD) instability is investigated experimentally both in and out of the plane of polarization of a CO₂ laser incident on an underdense gas target. The results presented here show that, for high intensities (I > ~ 3.5 x 10¹³ W/cm² for a helium target, 1 > ~ 5.5 x 10¹³ W/cm² for a nitrogen target), the electron plasma waves (EPW's) generated by the TPD instability are modified by the electron decay instability (EDI). The relatively short scale lengths at the onset of TPD for these high intensities (<~0.125mm) cause the EPW's propagating towards the higher density regions of the plasma to undergo the EDI resulting in EPW's which contain a vector component perpendicular to the plane of polarization and accelerate electrons by nonlinear Landau damping up to 55° outside the plane of polarization.
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