五矩多流体等离子体中热界面、同位素界面与组分界面的里希特迈耶-梅什科夫不稳定性
The Richtmyer-Meshkov Instability of Thermal, Isotope, and Species Interfaces in a five-moment multi-fluid plasma
- The University of Queensland（昆士兰大学）
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AI总结：
本研究采用多流体等离子体模型，模拟了热、组分、同位素界面的里希特迈耶-梅什科夫不稳定性，发现不同界面演化差异显著，电子流体密度比及离子-电子耦合程度是关键影响因素。
AI中文摘要：
里希特迈耶-梅什科夫不稳定性（RMI）源于密度界面的脉冲加速，该界面或加速过程存在扰动。密度界面可因气体组分、同位素、温度的变化或这些因素的组合而产生。我们通过计算研究了界面类型对等离子体RMI的影响，该研究与包括惯性约束聚变在内的一系列应用相关。我们采用多流体等离子体（MFP）模型，模拟了理想离子-电子等离子体中单模扰动的热界面、组分界面与同位素界面的演化。我们发现，在MFP模型中，不同类型界面的演化存在显著差异，这与单流体模型形成对比——在单流体模型中，若阿特伍德数匹配，这些界面的表现相似。热界面与组分界面对冲击加速产生最强烈的响应，会经历次级不稳定性并伴随基模增长增强；相比之下，同位素界面的演化受到抑制，与单流体模型预测的响应相似。MFP RMI响应强度的决定因素是电子流体中初始界面两侧的密度比，对于同位素界面，该密度比为1。我们观察到，随着电子界面两侧的密度比降低，自生场的幅值随之减小，进而增长放大的强度也降低。总体而言，随着离子流体与电子流体之间的耦合程度提高（以等离子体无量纲趋肤深度减小为特征），不同类型界面的RMI演化会变得更为相似。
英文摘要：
The Richtmyer-Meshkov instability (RMI) results from the impulsive acceleration of a density interface where either it or the acceleration is perturbed. Density interfaces may arise due to a change in gas species, isotope, temperature or a combination of these. We computationally investigate the effect of interface type on the plasma RMI, which is relevant for a range of applications, including inertial confinement fusion. We simulate the evolution of single-mode perturbed thermal, species and isotope interfaces in an ideal ion-electron plasma using the multi-fluid plasma (MFP) model. We find that in the MFP model, the evolution of different types of interface differ significantly, in contrast to single-fluid models where they behave similarly if the Atwood number is matched. The thermal and species interfaces produce the most severe response to shock acceleration, experiencing the secondary instabilities and enhanced primary mode growth. The isotope interface evolution is restrained in comparison to the former cases, resembling the response predicted by single-fluid models. The determining factor in the severity of the MFP RMI is the density ratio across the initial interface in the electron fluid, which is unity for an isotope interface. We observe that as the density ratio across the electron interface decreases, so do the magnitudes of the self-generated fields and consequently the severity of the growth amplification. Generally, the evolution of the RMI with different types of interface becomes more similar as the level of coupling between the ion and electron fluids is increased, characterised by reducing the plasma non-dimensional skin depth
