Laser amplification in an inhomogeneous plasma

The propagation of an electromagnetic wave into an inhomogeneous plasma was studied. In a plasma with large density gradients a QTX mode propagating perpendicular to the magnetic field can encounter a resonance and a cutoff separated by a distance comparable to the incident wave length. In this region the wave is evanescent, and in general there will be a reflected and transmitted wave, and amplification will occur in the region near the resonance. The amplification is important for the study of nonlinear phenomena and for feedback stabilization applications.