Waves and Instabilities in Steady-State High Beta Plasmas.
Final scientific rept.,
CALIFORNIA UNIV LOS ANGELES DEPT OF ELECTRICAL ENGINEERING
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Experimental simulations of laser-plasma interactions have been performed in the microwave region. Stimulated Brillouin scattering from transient density perturbations associated with the finite 1 chamber reflectivity has been observed. Saturation of the reflectivity has been observed at approximately 5 and the saturation mechanism identified as ion tail heating. The experimental results are in excellent agreement with numerical calculations of the density fluctuations and reflectivity which account for electron main body heating via inverse Bremsstrahlung absorption and ion tail heating. For the first time ion waves have been generated by optical mixing. The experimental results in the linear region were shown to be in excellent agreement with theoretical predictions. The saturation level was found to be identical to that seen in the pure SBS studies and shown to be also due to ion tail heating. Studies were made of resonance absorption produced electric fields and the associated hot electron production. At the lowest intensity levels the saturation was shown to be due to plasma wave convection out of the critical layer while at higher intensities it was due to cold plasma wavebreaking. Finally, finite bandwidth effects were investigated. Author
- Plasma Physics and Magnetohydrodynamics