电感分布对双层丝阵Z箍缩内爆动力学模式的影响

Effects of various inductances on the dynamic models of the Z-pinch implosion of nested wire arrays

采用等效电路和零维分析方法,建立了双层丝阵Z箍缩内爆动力学的物理模型.研究了内、外层丝阵电感分布及其变化对双层丝阵内爆动力学模式的决定性影响,结果表明丝阵的初始电感决定了初始电流分配,动态电感变化影响丝阵内爆的动力学过程.提出由于电感的变化可能存在四种不同的双层丝阵内爆动力学模式.针对"强光一号"装置Z箍缩双层丝阵负载参数进行计算分析,可以得到外层等离子体穿透内层先运动到芯的动力学模式,与其他低电流装置在实验上观察到的物理图像一致.

Z-pinch experiments have demonstrated that the soft X-ray power increases 40% with a nested-wire array compared with that with a single-layered wire array. However, the development of the technique of obtaining higher X-ray power using nested wire array configurations has been largely empirical. This has, in part, been due to the absence of adequate theoretical models to describe the mechanism of interaction of the two arrays. As is well known, 2D MHD modeling of nested wire array implosions is difficult, and is very inconvenient to optimize the design of nested-wire arrays. In this paper, the Z-pinch implosion dynamics of nested wire array has been described by its equivalent electric circuit and by solving the corresponding circuit equation. The currents flowing through the outer and inner arrays in the initial stage of implosion depend on the array dimensions, especially on the array inductances. The analysis indicates that the arrays inductance variation can result in four dynamic models of the Z-pinch implosion of nested wire arrays, which is the same as that predicted by previous works. Fast and inexpensive 0D modeling can predict the implosion time and the rate of thermalization of the kinetic energy of the nested-wire array at Qingguang-1 facility, and estimate the implosion model that the inner array wires remain discrete until the outer array material has passed through their gaps. The full current is then transferred rapidly to what was initially the inner, imploding it rapidly onto the outer array material on the axis. Some suggestions are put forward which may be helpful in the nested-wire array design for Z-pinch experiments.