A VARIATIONAL APPROACH TO PARAMETRIC-INSTABILITIES IN INHOMOGENEOUS PLASMAS .3. 2-PLASMON DECAY

The theory of the two-plasmon decay instability is recast in the form of a variational principle for the pump strength or intensity of the i ncident laser. This allows the calculation of growth rates, frequency shifts, and threshold conditions for two-plasmon decay modes that occu r in integer power law density profiles, including the effects of obli que incidence of the laser and both S and P polarizations. The transit ion between parabolic profiles occurring at the peak of an exploding f oil target and linear profiles on its flanks is treated as well.