Neon-filled glass spherical shell targets were irradiated by a four-beam laser system of incident power 0.6-0.8 TW. By measuring $K\alpha$ x-ray lines of neon and silicon we are able to determine the number of fast (nonthermal) electrons and their preheating effect. Correlation is made with fast ion measurements.

• Received 24 March 1976

DOI:https://doi.org/10.1103/PhysRevLett.37.836