Enhanced Laser-Light Absorption by Optical Resonance in Inhomogeneous Plasma

The collisional absorption of laser radiation by a planar plasma was calculated using the classical physical optics of absorbing media. In most regions of interest to thermonuclear fusion, the enhanced absorption of $p$-polarized radiation by optical resonance—particularly at high temperatures and long laser wavelength—completely dominates the ordinary absorption due to inverse bremsstrahlung.