The Numerical Simulation Of Xe Plasma Toroids Acceleration

The research on the acceleration technology of high-speed compact plasma toroid (CT) has great significance to the exploration of collision fusion, new type directed energy weapon, soft X-ray emitter, high-power microwave, etc.In this thesis, the inert gas Xenon (Xe) and Argon (Ar) are chosen separately as CT working substance, the CT's acceleration process in coaxial plasma gun is simulated numerically by means of whole model and radiation hydrodynamics (RHD) model. The Runge-Kutta method is used to solve the equation of acceleration current, the Lagrange formulation, implicit iterative algorithm and split scheme are adopted to solve the RHD equations. Using the electrical parameters of capacitors named SHIVA-STAR in Phillips laboratory, we obtained the evolution process of CT's parameters with time during acceleration, such as current, speed, kinetic energy, position, resistance, temperature and so on, and studied the influence of initial conditions on CT acceleration process, such as accelerator's inner and outer radii, capacitor's capacity and voltage, mass and working substance of CT.In the whole model, the CT is viewed as a good conductor which can freely glide along the coaxial plasma gun, much like the electromagnetic gun principle. Main evolution parameters of 1mg, 10mg and 100mg CT are obtained during acceleration process, such as current, speed, kinetic energy, position and so on. On one hand, this model can provide valuable reference data for the design of acceleration facility, on the other hand, it can provide the most superior initial conditions to RHD simulation followed.To obtain more precise results and investigate CT internal non-uniformity, RHD model is established. In this model, CT is regarded as a magnetic fluid. By numerical simulation of 10mg Ar and Xe CT, the evolution images of CT resistance and temperature with time in the process of acceleration are obtained, and more precise information of parameters are given, such as current, speed, kinetic energy, position, as well as detailed distribution of temperature and speed within the interior of CT.Prior to the solution of the RHD equations, we calculated the average ionization and opacity of Ar and Xe plasma in the range of [10^-8, 0.1] (g/cm³), [0.01, 100](10⁶K) in terms of average atom model (AA), and fit them into a continuous function of temperature and density, which are indispensable parameters in solving the RHD equations.