Time of flight measurements on ion-velocity distribution and anisotropy of ion temperatures in laser plasmas.
Using a 200-mJ, 5-ns, Nd:YAG laser (where YAG denotes yttrium aluminum garnet), time of flight spectra for ions produced from slab targets of carbon, aluminum, nickel, and tantalum were obtained at a laser intensity of approximately 5x10(10) W/cm(2). The velocity distribution function of ions of each ionization state, at several angles, in the plane of incidence, was investigated and was observed to depart significantly from the Maxwell-Boltzmann distribution function. Kinetic temperatures of ions of each ionization state were estimated separately at various angles in the plane of incidence and were observed to show a highly anisotropic property leading one to conclude that the equipartition of energy between the plasma electrons and ions has not taken place. The results are discussed and the relevant conclusions are presented.
Thum-Jaeger
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A
Fachbereich Physik, Universität Kaiserslautern, D-67663 Kaiserslautern, Germany.
Sinha
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BK
Rohr
K P
KP