Nanosecond and picosecond laser-produced CD2 plasmas

Abstract

A preliminary comparison is made of plasmas created by irradiation of CD2 slab targets by single high‐energy Nd3+glass laser pulses of 3.5‐nsec (35 J max) and 3–10‐psec (10 J max) duration. For the nanosecond irradiations we find electron temperatures of 350–400 eV and appreciable C5+ ions at 20‐keV expansion energy. Ion expansion energies for a picosecond pulse are about one‐third those for a nanosecond irradiation of comparable energy. Up to 50% of the incident pulse energy may be accounted for in plasma expansion in either case. In each case, the specularly reflected energy back into the input f/5.0 lens is small: 0.4% and 0.8% for the nanosecond and picosecond times, respectively. Detailed ion analysis shows the target composition to be CD2−x H x , where 0.2<x<0.9 with traces of oxygen also observable.