Multi-wire Z-pinch Research Articles

Generalized computational ablation model of multi-wire cylindrical Z-pinches

The generalized computational ablation model of multi-wire Z-pinches is developed. Using derived equations, one can calculate at each moment of time both the mass ablation rate from single and nested cylindrical wire arrays as well as the matter ablation velocity. These two important variables provide the capability to numerically simulate high energy density Z-pinch experiments in a wide range of load parameters: the initial multi-wire array radius up to tens of centimeters, the inter-wire gap up to a few millimeters, the Z-pinch implosion time up to a few microseconds, and the current amplitude in a load up to tens of mega-amperes. The generalized ablation model makes it possible to reproduce the main characteristics of the Z-pinch implosion, such as the moment of starting and following movement trajectory of current-plasma sheath, timing of x-ray pulse generation, its duration, x-ray power, and total radiation energy, in radiative magneto-hydrodynamic calculations. The generalized computational ablation model of tungsten multi-wire Z-pinch was validated using results of experiments with explosive magneto-cumulative generators (Russia) and was applied further to various pulsed power generators such as Z-accelerator, PTS, MAGPIE, and Angara-5-1.

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 ${r}$ - $\varphi $ - ${z}$ 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 ( $2\pi $ ) 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 3-D 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.

Three-dimensional simulation of magneto-hydrodynamic implosion of multi-wire cylindrical liners by the FLUX-3D code

A three-dimensional magneto-hydrodynamic model of conductive radiating plasma, underlying the Euler (in the cylindrical coordinates r-φ-z) program code FLUX-3D, developed at the Russian Federal Nuclear Center VNIIEF, is presented. Finite-difference methods for solving the equations of the model on a stationary regular spatial grid are described. Results of numerical 3D simulation of a multi-wire Z-pinch in conditions of the Shot-51 experiment on electrophysical facility Z (USA) in the full (2π) azimuth angle are presented. The computation geometry has been approximated to the real experimental configuration, in which the electromagnetic energy was supplied to the chamber by a vacuum coaxial transmission line. In the numerical simulation, the dynamics of the acceleration of plasma ablated from tungsten wires as a function of the number of wires in the initial cylindrical assembly was studied. In addition, results of 3D calculations of the current implosion of multi-wire Z-pinch for two kinds of artificial perturbations on the plasma ablation intensity are presented. The reasons of the difference in the soft X-ray radiation pulses generated in these cases are discussed.

单丝及多丝Z箍缩的X射线背光成像

单丝及多丝Z箍缩的X射线背光成像

The effect of an initial load twist on Rayleigh-Taylor instability growth and X-ray radiation of wire-array Z-pinches

Initially twisted multiwire Z-pinch loads (Volkov et al., 1998; Golub, 1999) are expected to significantly improve the performance of these X-ray sources. A model based on the self-consistent simulation of the dynamics of a twisted plasma shell and the development of Rayleigh-Taylor (RT) perturbations on a plasma surface is proposed to quantitatively study the effect of various physical factors on the generation of X-rays. The model provides us with a tool for the analysis of processes that occur during the implosion of the plasma-shell-wire-core system. We plan for the RT perturbations to break through the plasma shell at the moment when the internal radius of a shell becomes zero, where the greatest possible values of kinetic energy and X-ray radiation power ought to be obtained. The results of numerical simulations for the Sandia National Laboratories' Z-generator are presented and discussed.