A novel equivalent electric network approach for the 3-D MHD modelling of EML plasma armatures

Abstract

In this paper an equivalent network model for the three-dimensional analysis of an EML (electromagnetic launcher) plasma armature is presented. We decompose the plasma armature in elementary volume elements in which a uniform distribution of the current density, momentum density and heat flux is assumed. A first equivalent electric network is obtained for the determination of the current density and magnetic field distribution in the plasma arc at each time step. Assuming the same plasma arc decomposition, and defining a formal analogy between thermodynamic and electric quantities in the momentum and mass conservation equations, we obtain a second equivalent electric network that allows the determination of the pressure and the mass density distribution and the internal motions in the plasma arc at each time step. Adopting the same procedure, we obtain another equivalent network from the energy equation that allows the determination of the temperature in the plasma arc at each time step. The ionisation coefficient distribution is calculated from Saha's equation. Considering an isothermal plasma with no ablation, calculated results are reported to show the influence of the 3-D model on the distributions of the main thermodynamic quantities of the plasma arc. >