Laser interactions with plasmas

The availability of high power CO2 lasers has permitted the investigation of laser interactions with plasmas in magnetic fields. A quantitative investigation of the breakdown of gases in a magnetic field by laser radiation has been made. The breakdown threshold has been reduced with increased magnetic field due to the reduction in diffusion losses transverse to the magnetic field. Magnetic field enhancement of the heating of a laser-produced plasma has also been predicted by theoretical calculations. Experimental measurements of electron temperature using the He II line-to-continuum ratio technique have qualitatively confirmed this prediction. In addition, experiments which demonstrate the existence of beam-trapping density profiles in the presence of a magnetic field have been performed