Numerical Simulation of Multiwire Z-Pinches Within the Framework of 3-D Magnetohydrodynamics

This paper presents a 3-D magnetohydrodynamic model of a conducting radiating plasma, which forms the basis for the Euler (in r-φ-z cylindrical coordinates) FLUX-3-D computer code. Finite-difference methods used to solve the model equations on a stationary regular spatial grid are described. The numerical 3-D simulations of a multiwire Z-pinch based on Shot-51 experiment on Z facility machine (USA) are given for the full (2π) azimuth angle. The computational geometry was approximated to the real experiment configuration wherein the electromagnetic energy was supplied to the liner chamber using a vacuum coaxial transmission line. During numerical simulations, the acceleration dynamics of the plasma ablated from tungsten wires was studied depending on their number in the original cylindrical array. In addition, the results of 3D multiwire Z-pinch implosion calculations are considered for two ways of an artificial perturbation imposition on the plasma ablation intensity. The causes for the difference in soft X-rays pulses generated in these cases are discussed.

I. Introduction

To provide a calculation and theoretical support for the liner experiments aimed at generating soft X-rays (SXRs) pulses and compressing the initial magnetic flux, RFNC-VNIIEF had previously developed a 2-D (in Euler rz cylindrical coordinates) radiation magnetohydrodynamic (RMHD) FLUX-rz procedure. It was successfully applied for numerical simulations of the experiments with dynamic - [1] and - [2] pinches powered by current pulses from magnetocumulative generators. FLUX-rz computer code made it possible to calculate the plasma heat radiation transfer in a multigroup (spectral) approximation [3].