兆安级电流下Al丝阵的芯晕结构抑制研究

为了抑制丝阵Z箍缩中金属丝在电流早期电爆炸形成的芯晕结构，基于强光一号加速器，利用二级丝阵负载开展了Al丝阵早期物理状态的调控研究。通过陡化预脉冲和调整二级丝阵的参数，实现了负载Al丝的全部汽化，抑制了芯晕结构的产生，气态Al丝芯的平均直径约为1.80 mm，且沿轴向均匀分布，降低了丝阵消融引起的初始不稳定性。若丝长度和直径保持不变，反转型丝阵的关断时间主要取决于Al丝的丝数；反转型丝阵关断后，气态丝芯在主电流脉冲作用下迅速电离并开始内爆，磁瑞丽泰勒不稳定性迅速发展，内爆等离子体流沿轴向呈周期性调制分布，调制波长约为650 μm。Al丝阵初始状态的改变，有效抑制了丝的消融过程，消除了先驱等离子体，在内爆后期降低了拖尾质量，提高了箍缩品质。

Study on Core-corona Suppression of Aluminum Wire Array with Megampere Current

In order to suppress the core-corona structure resulting from the initial single-wire exploding phase of wire array Z-pinch, two-stage aluminum wire array experiment was carried out on Qiangguang-Ⅰ to control the initial state of aluminum wire. Aluminum wire in top array was completely vaporized and core-corona structure was suppressed by steeping pre-pulse current and adjusting the parameter of two-stage wire array. Aluminum wire expanded to a diameter about 1.80 mm homogeneously along the axis, which reduced the initial instability caused by typical wire ablation. The switch time of inverse array mainly depends on the number of aluminum wire when wire length and diameter remain unchanged. The magneto Rayleigh-Taylor instability develops rapidly during the implosion of top array. The inward plasma stream is periodically modulated along the axis with a wavelength about 650 μm. The wire ablation as well as the precursor plasma is effectively suppressed for the change of initial wire state. The trailing mass at late implosion phase is reduced and the pinch quality is improved.