The Generation of Warm Dense Matter Samples Using Fast Magnetic Compression
The Generation of Warm Dense Matter Samples Using Fast Magnetic Compression
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DOI：
10.1109/tps.2015.2453933
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发表时间：
2015-08-01
影响因子：
1.5
通讯作者：
Gourdain, Pierre-Alexandre
中科院分区：
文献类型：
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作者：
Gourdain, Pierre-Alexandre
我们对暖致密物质（WDM）性质的理解将有助于揭示巨行星的形成和演化，包括气态巨星或巨型地球。然而，实验室中WDM的生产仅限于几十微米量级的样品。这给使用标准诊断来测量WDM的特性带来了许多挑战。在本文中，我们提出了一种新的方法来生产WDM样品使用脉冲功率机。我们的数值模拟表明，早期的膨胀阶段的样品，通常会遇到脉冲功率系统，可以几乎消除使用电流开关计划。为了避免混合等离子体和WDM状态，本策略使用喷气Z箍缩作为闭合等离子体开关。在放电的第一部分期间，大部分电流在喷气Z箍缩内流动，防止样品加热。在这个阶段，气体Z箍缩径向收敛到样品。当Z箍缩最终到达样品时，所有的Z箍缩电流切换到样品并迅速加热样品。Z箍缩产生的强方位场阻止了样品的膨胀。如果仔细选择初始气体压力，则样品达到准均匀WDM状态。该方法的效率允许一个500 kA的脉冲发生器产生毫米大小的WDM样品。
Our understanding of warm dense matter (WDM) properties will help to unravel the formation and evolution of giant planet, including gaseous giants or mega-Earths. However, the production of WDM in the laboratory is limited to samples on the order of tens of micrometers. This raises many challenges to measure the properties of WDM using standard diagnostics. In this paper, we propose a new method to produce WDM samples using pulsed-power machines. We numerically demonstrate that the early expansion phase of the sample, usually encountered in pulsed-power systems, can be virtually eliminated using a current switching scheme. To avoid mixing the plasma and WDM states, the present strategy uses a gas-puff Z-pinch as a closing plasma switch. During the first part of the discharge, most of the current flows inside a gas-puff Z-pinch, preventing the heating of the sample. During this phase, the gas Z-pinch radially converges toward the sample. When the Z-pinch finally reaches the sample, all the Z-pinch current switches to the sample and rapidly heats it. The strong azimuthal field generated by the Z-pinch prevents the expansion of the sample. If the initial gas pressure is carefully chosen, the sample reaches a quasi-homogeneous WDM state. The efficiency of the method allows one to produce millimeter-size WDM samples with a 500-kA pulser.