MHD simulation of conical plasma liners implosion

Abstract

MHD numerical simulations are applied for multiparameter studies of quasi-spherical magnetic compression of plasma liners created by conical multiwire arrays electrical explosion at ANGARA-5-1 facility (TRINITI) with the discharge current 2 to 3 MA and the pulse rise time about 100 ns. The description of the plasma dynamics at different stages of implosion is reproduced as a result of simulation. Numerical and experimental time profiles of voltage drop at the load and soft X-ray yield power are compared. The effect of the geometry changes upon the implosion process is studied. Numerical simulation is based on 2D RMHD code MARPLE (IMM RAS) using unstructured triangular grids. The code implements one-fluid two-temperature MHD model, grid-characteristic method for radiative energy transfer and the model of prolonged plasma ablation to simulate plasma source. The governing MHD system of is completed by electrical equation for the full circuit including the generator itself, leading-in systems and the discharge chamber with the plasma in it. Equations of state, transport and kinetic coefficients, opacity and emissivity coefficients are taken from the tables. The behavior of the discharge is satisfactorily described in general by the above RMHD model. The plasma ablation model appeared to have a significant effect on both the entire scheme of plasma dynamics and such values as voltage drop at the load and soft X-ray yield power. The improvement of this model based on experimental and theoretical estimations is an issue of the day in 2D and 3D Z-pinch simulations. The MARPLE code calibrated against the conical liners simulations proved to be a useful tool for computations aimed to optimization of the experimental setup for 3D implosion of plasma.