Nonlinear Laser Heating of a Plasma.
Technical rept. 1 Mar 71-29 Feb 72,
HUGHES RESEARCH LABS MALIBU CALIF
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The heating of a dense plasma by a laser through the exciation of parametric instabilities is examined in detail. These instabilities convert laser energy into plasma density fluctuations or waves which ultimately result in particle heating by collitionless and collisional wave damping. A comprehensive nonlinear weak-turbulence theory of the saturation of these instabilities is developed, and the saturated plasma wave spectrum for the case of nearly equal electron and ion temperatures is computed. The saturated wave level permits the calculation of the nonlinear absorption coefficient of the laser which can be considerably enhanced over the linear inverse bremsstrahlung value for typical laser power densities. The self-consistent propagation of the laser beam, including this nonlinear absorption in an overdense inhomogeneous plasma, is studied in a one-dimensional model and the reflection coefficient as a function of incident power is computed. Author
- Plasma Physics and Magnetohydrodynamics