The Effects Of The Radial Mass Distribution On The Implosion Dynamics Of Wire Array Z Pinches

The intense X-ray radiation produced by wire array Z-pinch implosion has widely applications, including inertial confinement fusion, high energy density physics and laboratory astrophysics. Wire array with good quality of the initial axial symmetry can be precisely controlled as the major load configuration at present Z-pinch experiments. It makes people of great interest for the wire array Z-pinch implosion dynamics while obviously the mass distribution is a significant factor affecting wire array Z-pinch implosion. The shin shell model considering that the mass concentrates in the infinitely thin annular shell driven by magnetic pressure, is used to describe the behavior of wire array implosion earlier, while the actual implosion process is more complex. Firstly, ablation plasma existed on the earlier stage of implosion makes wire array implosion trajectory and shell model predictions are very different. Such implosion behavior is more similar to snow-plow implosion due to the inner mass modulation during implosion process. Secondly, there exists mass distribution inner wire array itself in some combined load configurations associated with ICF research. The effect of mass distribution on the implosion dynamics is also concerned.Rocket model is a simple model of dealing with ablation plasma. We establish a whole ablation-implosion dynamics model combined rocket model and snow-plow model. In comparison with shell model, the result is that the maximum kinetic energy is smaller due to the ablation plasma and optimization of line mass will be significantly lower. We make an analysis of the wire array configuration of the foam cylinder within the load by snow-plow model and results show that the mass distribution of internal load will decrease the implosion kinetic energy. Proposed of the circular foam cylinder configuration, the calculation results suggest that the smaller the thickness of the circular foam cylinder, the greater the implosion kinetic energy as the implosion time is smaller. When the thickness is significant small, we can approximately simulate the collision model of nested wire-array and the results are similar with the results of foam cylinder. Moreover, considering the plasma pressure, the shin shell model adding pressure effect and coupling the equivalent circuit model can simulate the wire array implosion and the reasonable convergence and implosion trajectory could be obtained selecting appropriate parameters.