Abstract

A characteristic feature of the implosion of multiwire arrays on powerful high-current electrophysical facilities (ZR, Angara-5-1, Julong-1 (PTS), MAGPIE, etc.) is the process of extended wire ablation. It is based on the fact that the substance of the wires is not converted into plasma instantly, but is supplied into the discharge relatively slowly at the rate \(\dot {m}(t)\) in about 70–80% of the rise time of the facility current. It is believed that the plasma is formed on the surface of the cores of the exploded wires due to the energy coming from the hot plasma corona surrounding the core of the wire in the form of the heat flux and emission. In this paper, we propose a new approach to determining the quantity \(\dot {m}(t)\) as the main quantitative characteristic of the process of the extended wire ablation in wire (or fiber) arrays. A method is presented, using which it is possible to determine experimentally the time dependence of the quantity \(\dot {m}(t)\) both at the initial stage of the plasma formation and at its final stage, when \(\dot {m}(t)\) → 0. In fact, by measuring the current I_p with a magnetic probe located inside the wire array near the surface of the wires, it is possible to find the current flowing in the plasma formation region I_s as the difference between the total current through the liner and the current I_p. The time dependence I_s(t) thus defined is nonmonotonic, and the quantity \(\dot {m}(t)\sim I_{s}^{2}\left( t \right)\) correspondingly decreases at the final stage of the implosion of the wire array. The intensity of the plasma formation of arrays made form wires and fibers of different substances (Al, Cu, Mo, W, Bi, and kapron) was determined in experiments at the Angara-5-1 facility, the decay rate of this quantity at the stage of the plasma formation termination and its effect on the pulse and emission parameters were analyzed. The obtained results are compared with the data of the numerical MHD simulation.

中文翻译：

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不同物质圆柱线和纤维阵列在电流内爆时等离子体形成强度的时间依赖性研究

摘要

强大的高电流电物理设施（ZR，Angara-5-1，Jurong-1（PTS），MAGPIE等）上的多线阵列爆破的一个特征是延长线烧蚀的过程。这是基于这样一个事实，即导线中的物质不会立即转换成等离子体，而是在大约70-80％的放电速率中以\（\ dot {m}（t）\）的速率相对缓慢地供应到放电中。设施电流的上升时间。据信，由于来自热等离子体电晕的能量以热通量和发射的形式来自围绕金属丝芯的热等离子体电晕，所以在爆炸金属丝芯的表面上形成了等离子体。在本文中，我们提出了一种确定数量\（\ dot {m}（t）\）的新方法作为线（或纤维）阵列中扩展线烧蚀过程的主要定量特征。提出了一种方法，使用该方法可以通过实验确定量\（\ dot {m}（t）\）在等离子体形成的初始阶段和最终阶段（当\（\点{m}（t）\） →0。实际上，通过使用位于线表面附近的线阵列内部的磁探针测量电流I _p，可以找到在等离子体形成区域中流动的电流I _s是通过衬管的总电流与电流I _p之差。时间的关系我_小号这样定义的（t）是非单调的，并且\（\ dot {m}（t）\ sim I_ {s} ^ {2} \ left（t \ right）\）的数量在内爆的最后阶段相应减少线阵列。由不同物质（Al，Cu，Mo，W，Bi和kapron）的金属丝和纤维制成的阵列的等离子体形成强度是在Angara-5-1设施的实验中确定的，该量的衰减速率为分析了等离子体形成终止的阶段及其对脉冲和发射参数的影响。将获得的结果与数值MHD仿真的数据进行比较。