Excitation of Langmuir waves by two pumping waves in homogeneous plasma

Considered is a nonlinear excitation by two plane polarized electromagnetic waves of high frequency plasma potential perturbations in inhomogeneous plasma region, where the difference in frequency of outer waves is close to doubled Langmuir frequency. On the basis of the solution of the system of shortened equations for perturbed plasma amplitudes it is shown that at given resonance the convective instability is possible. An amplification factor of excited waves appears to be rapidly reducing temperature function (proportional to exp. (cT-3), that is why the process considered is most effective at the first stage of plasma heating