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P: Plasmaphysik
P 13: Schwerionen- Laserplasmen I, Dichte Plasmen I
P 13.4: Fachvortrag
Mittwoch, 10. März 2004, 11:50–12:10, H\"orsaal H
Energy-transfer and expansion-dynamics of a collisional laser-plasma from planar, atomic and binary targets — •B. K. Sinha1, S. N. Srivastava2, and K. P. Rohr2 — 1Bhabha Atomic Research Center, Mumbai, India — 2Fachbereich Physik, Universität Kaiserslautern, Germany
Time of flight spectra of ions from plasmas produced from planar, monoatomic targets of copper and tungsten as well as binary targets of copper and tungsten, with two different stoichiometric compositions, have been obtained using 130 mJ, 5nsec, Nd:YAG laser pulses, at a laser intensity of about 8x109W/cm2. Angular variations of average velocity and kinetic energy of ions from these plasmas are reported. The average ionization degrees, summed over all the ions as well as over all the ions and neutrals, have been obtained as a function of angle with reference to the target-normal. Fractions of neutral atoms as well as the ions are also presented. It was observed that the significant energy-transfer from the lighter to the heavier ions does take place, which is in a good agreement with the results obtained from Monte-Carlo simulations. Energy-transfer among the ions of the same species, but with different degrees of ionization, has also been observed. Measurements on the average ionization-degree show the existence of a strong recombination mechanism indicating a definite role for it in the energy-transfer.