A global theoretical approach for the electrothermal gun: scaling laws and a 0-D time-dependent model

In this paper, a theoretical analysis of the physical processes taking place in the electrothermal gun is presented. In a first step, using the basic conservation equations (energy, mass, charge) integrated over the whole time of the discharge, scaling laws are derived. These laws provide the temperature, the mass, the resistance of the plasma and the current going through it, as functions of the stored electrical energy. In a second step, a 0D time-dependent model is presented. This model takes into account the evolution of the complete system consisting of the electrical source, the plasma burner and the motion of the projectile. Special attention is given to the ablation phenomena and a microscopic description which differs from prior publications is derived. Finally, comparisons with experiments are given and good agreements are obtained.<>