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Title: The role of radiative reabsorption on the electron energy distribution functions in H{sub 2}/He plasma expansion through a tapered nozzle

A collisional-radiative model for the H{sub 2}/He plasma, coupled to a Boltzmann solver for the free electron kinetics is used to investigate the non-equilibrium conditions created in the expansion of an high-temperature plasma flow through a converging-diverging nozzle, starting from the steady state composition at T{sub 0}=10 000 K and p{sub 0}=1 atm in the reservoir. It is shown that the plasma optical thickness plays a major role on the evolution of macroscopic quantities and internal distributions along the nozzle axis. Structured electron energy distribution functions, characterized by long plateaux and humps, are created due to superelastic collisions of cold electrons and electronically excited atomic hydrogen. The magnitudes of the plateaux are orders of magnitude higher in an optically thick plasma compared with a thin plasma, while the electron-electron collisions play a role in smoothing the peaks created by superelastic collisions between cold electrons and H(n>2)
Authors:
;  [1] ;  [2] ; ; ; ;  [3]
  1. Dipartimento di Chimica, Universitá di Bari, Via Orabona 4, 70125 Bari (Italy)
  2. (Italy)
  3. CNR-IMIP, Via Amendola 122/D, 70126 Bari (Italy)
Publication Date:
OSTI Identifier:
22303667
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 9; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; COMPARATIVE EVALUATIONS; ELECTRON-ELECTRON COLLISIONS; ELECTRONS; ENERGY SPECTRA; HOT PLASMA; OPTICALLY THICK PLASMA; PLASMA EXPANSION; STEADY-STATE CONDITIONS