Nonlinear resonance absorption of laser in an inhomogeneous plasma

Abstract

A formalism of nonlinear resonance absorption of p-polarized laser in a plasma with density gradient is developed. The nonlinearity is taken to arise through the relativistic mass effect. As the laser incident at an angle to the density gradient approaches the turning point, dielectric swelling leads to field enhancement, causing strong electron mass enhancement and reduction in local plasma frequency. When the critical layer is within a laser wavelength away from the turning point, the laser field is greatly enhanced at the critical layer and absorption of the laser is strongly affected by the nonlinear effect.