Semi-analytical modelling and simulation of the evolution and flow of ohmically-heated non-ideal plasmas in electrothermal guns

In this paper, the Ohmic power input to the discharge capillary is recovere d and used to analyse the basic processes involved in electrothermal (ET) p lasma devices operated in an ablation-controlled-arc regime. Such an interp lay between theory and experiment is necessary to reduce the number of reas ons which might be responsible for the reported discrepancies between theor y and experiment, as well as to illuminate the subject of ablation controll ed arcs. A consistent methodology for determining detailed composition and thermodynamic functions of the non-ideal plasma generated in such devices i s presented and used in the present computations. Different non-ideality ef fects, due to Debye-Huckel corrections in the Gibbs free energy, which have been ignored in prior publications, have been taken into account. A semi-a nalytical model for an ET plasma source with non-ideal effects is described and incorporated into a comprehensive computer code to simulate plasma evo lution and flow in the discharge capillary. The model is one-dimensional, t ime dependent and uses the recovered Ohmic power input in the source term o f the energy equation. The developed code has been used to investigate the ablation process and has shown the inappropriateness of a widely used ablat ion model. Code predictions for different plasma parameters are presented, discussed, and compared to available experimental data.