A two-component model for the electron distribution function in a high-current pseudospark or back-lighted thyratron

Abstract

Temperature, energy, and densities of two electron distribution function components, including an isotropic bulk part and an anisotropic beam, are analyzed for a hydrogen pseudospark and/or back-lighted thyratron switch plasma with a peak electron density of 1-3*10/sup 15/ cm/sup -3/ and peak current density of approximately=10/sup 4/ A/cm/sup 2/. Estimates of a very small cathode-fall width during the conduction phase and high electric field strengths lead to the injection of an electron beam with energies >or=100 eV and density of 10/sup 13/-10/sup 14/ cm/sup -3/ into a Maxwellian bulk plasma. Collisional and radiative processes of monoenergetic beam electrons, bulk plasma electrons and ions, and atomic hydrogen are modeled by a set of rate equations, and line intensity ratios are compared with measurements. Under these high-current conditions, for an initial density n/sub H2/=10/sup 16/ cm/sup -3/ and electron temperature of 0.8-1 eV, the estimated beam density is approximately=10/sup 13/-10/sup 14/ cm/sup -3/. These results suggest the possibility of producing in a simple way a very high-density electron beam.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>