J. Phys. IV France 10 (2000) Pr5-409-Pr5-415
Suprathermal hard X-rays and energetic particles from plasmas "dust"Yu.K. Kurilenkov1, M. Skowronek2, G. Louvet2, A.A. Rukhadze3 and J. Dufty4
1 Institute for High Temperatures, IVTAN, Russia Academy of Sciences, 127412 Moscow, Russia
2 Laboratoire des Plasmas Denses, Université Pierre et Marie Curie, 75252 Paris cedex 05, France.
3 Institute of General Physics, Russian Academy of Sciences, Vavilova Str., Moscow, Russia
4 University of Florida, Gainesville, FL 32611, U.S.A.
This work concerns some novel aspects of the simple production of high power density matter in vacuum discharges [1,2] and related energy transport. We study the ensembles of cold grains - hot microplasmas created by an intense energy deposition into the cold solid density, low volume dust "target" collected in the interelectrode space (clusters, grains, microparticles of different size from anode material). Some effects of the high local power density were realised to allow production of the different ensembles of cold grains with fraction of hot microplasmas (T ˜ 1 KeV and ne ˜ 1020-1022 cm -3). The hard x-ray yield registered and well reproduced in the vacuum discharges (just at ˜ 1 J of energy stored) is about 0.1 - 0.3%. Time of flight measurements show that hard x-ray production may be accompanied by energetic ions (˜ 0.1 -1 MeV) like those for irradiated clusters . Thermal and suprathermal levels of x-ray emission, laser-like behaviour of potentially amplifying media of plasmas "dust" as well as x-ray trapping are discussed. The last phenomenon suggests a partial "random walk" of photons inside of x-ray "ball" due to the regulated level of multiple scattering and reflecting in disordered media of cold and hot "grains" of any sizes (x-ray "random" laser [4,5]). Single pass ASE  regime of x-ray lasing as particular case of x-ray yield is considered also.
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