Nanosecond and picosecond laser-produced CD2 plasmas

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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−xHx, where 0.2<x<0.9 with traces of oxygen also observable.