Effect of detuning on the beat wave saturation amplitude in a plasma

The asymptotic behavior of an electron plasma wave excited by two collinear laser beams, and its bistability, is studied analytically. The results show that the normalized detuning D has an important effect on the plasma wave reaching its maximum saturation amplitude level amax, for cases where D is larger than the normalized collision damping δ. Under the experimental conditions presently existing, the approximate formula is obtained for the maximum saturation amplitude amax, which is approximately in direct proportion to the square root of the detuning D. It is also found that the detuning D, or the normalized plasma density mismatch, must be reduced to less than 0.14 in the experiment. (author)