Suprathermal hard X-rays and energetic particles from plasmas "dust"

Abstract

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 n e ∼10 20 -10 22 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 [3]. 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 [6] regime of x-ray lasing as particular case of x-ray yield is considered also.