Simulation Of The Z-pinch Dynamic Black Cavity Formation Process Based On The MULTI2D-Z Program

The radiation hydrodynamic code MULTI2D has been modified to develop as a radiation magnetohydrodynamic code MULTI2D-Z by adding the programm module of evolution equation of magnetic field,and self-consistently considering the Lorentz force in the module of motion equation and the Ohmic heating in the module of energy equation.The newly developed module for magnetic field was validated to be reliable.The module is used to study the magnetic field diffusion process,and it is found that the diffusion is weakened duo to the increasing plasma temperature and density and the fluid convection,in which there is minus grads of velocity in radial direction.The new code is used to simulate the forming process of dynamic hohlraum driven by tungsten wire-array Z-pinch at 8MA current level.The simulated X-ray power(?30TW)and energy(?300kJ),radiation temperature in foam(?120eV),and the implosion trajectory of wire-array are theoretically reason-able.Calculated results reveal that the magnetic field is mainly distributed in the outside tungsten plasma during the hohlraum formation.The foam is expanding due to the radiation heating from the imploding wire-array plamsa.The thermal radiation wave,which is characterized by radiation temperature,spreads toward-s center axis faster than the plasma temperature.When the thermal radiation wave spreads to the center axis,the radiation temperature becomes comparative-ly uniform,and almost equates to the plasma temperature besides at the place of the shock wave.These results help the people to better understand the magnetic field diffusion and convection in Z-pinch,as well as the formation mechanism of dynamic hohlraum driven by wire-array Z-pinch.It is also indicated that the developed code MULTI2D-Z can be considered as a new tool for simulations of Z-pinch and its applications.We observe that the radiation temperature of hohlraum increases as the elec-tric peak current increases.In addition,the influence of the ring baffle position on the uniformity of the radiation field is observed in the process of hohlraum formation with the presence of ring baffle.By changing the materials of wire-array,we obtain a better understanding about the effects of material radiation parameter on the radiation temperature and uniformity.Finally,by simulating the dynamic hohlraum with an embedded center target,we observe that the ra-diation ablation of target results in the process of nuclear fusion,which further deepens the understanding of the process of inertial confinement fusion driven by the Z-pinch driven dynamic hohlraum.