Abstract

Thin CH foils (1-3 μm) have been irradiated with one beam of the Novette laser to produce exploding high-temperature plasmas having long scale lengths. These long- scale-length plasmas are important since they approximate plasma conditions predicted for reactor-size targets. In these experiments we irradiate the foils with 3-4 kJ of 0.532-μm light in a 1-nsec Gaussian pulse at peak irradiances of 3 × 10¹⁴ to 10 × 10¹⁴ W/cm2, Under these conditions the foil expands to densities less than critical density around the peak of the laser pulse, producing large scale lengths of underdense plasma where parametric absorption processes can occur producing high-energy superthermal electrons. We have used x-ray spectroscopy to help diagnose the plasma temperature and density of the exploding foil.

© 1984 Optical Society of America