The heating mechanism of electrons in the shock front of an expanding plasma

The heating of the electron gas in the shock front of an expanding plasma jet is modelled. In the expansion, due to the large pressure gradient, a current is generated which, besides the heating by three-particle recombination, takes care of additional heating of the electron gas. It is shown, by means of a quasi one-dimensional model in combination with a two-dimensional calculation of the electrical properties, that the preheating of the electron gas in front of the shock can be explained by Ohmic dissipation of the generated current density in combination with the electron heat conduction. The outcome of the model is compared with experimental results.