弱碰撞、高β等离子体中微湍流抑制平行热传导的实验观测
Experimental observations of microturbulence-suppressed parallel heat conduction in a weakly collisional, high-\b{eta} plasma
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中文总结 AI 辅助
在Orion激光设施上实验证实，高β弱碰撞等离子体中磁微湍流可将平行热传导抑制至少一个数量级，为修正热传导理论提供了首个实验室证据。
中文摘要 AI 辅助
磁化等离子体中热传导的经典理论预测，由电子库仑碰撞介导的热输运主要沿磁场线发生。近期的理论和计算研究对弱碰撞、磁化等离子体的这一描述提出了挑战，在这些等离子体中，热压主导磁压（即所谓的高β等离子体）。此类等离子体包括星系团内的介质和惯性约束聚变热点，被认为容易受到动力学尺度微不稳定性影响，这些不稳定性可以抑制平行热传导。已提出了考虑这些不稳定性的修正热传导理论，但缺乏用于验证这些理论的实验数据。在此，我们报告了在Orion激光设施上进行的实验，其中高β、弱碰撞等离子体的温度随时间演化主要对其初始准层流磁场方向上的热导率敏感。我们使用X射线光谱学和成像以及质子成像来表征温度、密度和磁场。一旦随机磁涨落发展起来，测得的温度演化要求热传导相对于经典预测至少被抑制一个数量级，这提供了首个将磁微湍流与高β等离子体中热传导抑制联系起来的实验室证据。
英文摘要
Classical theories of heat conduction in magnetized plasma predict that thermal transport, mediated by Coulomb collisions of electrons, occurs predominantly along magnetic field lines. Recent theoretical and computational studies challenge this description for weakly collisional, magnetized plasmas in which thermal pressure dominates magnetic pressure (so-called high-\b{eta} plasmas). Such plasmas, which include the intracluster medium of galaxy clusters and inertial-confinement-fusion hot spots, are thought to be susceptible to kinetic-scale microinstabilities that can suppress parallel heat conduction. Revised theories of heat conduction accounting for these instabilities have been proposed, but experimental data with which to benchmark them are lacking. Here, we report experiments at the Orion laser facility in which the temporal evolution of temperature of a high-\b{eta}, weakly collisional plasma is sensitive primarily to the thermal conductivity along its initially quasi-laminar magnetic field. We characterize the temperature, density and magnetic field using x-ray spectroscopy and imaging, and proton imaging. Once stochastic magnetic fluctuations develop, the measured temperature evolution requires suppression of thermal conduction by at least an order of magnitude relative to classical predictions, providing the first laboratory evidence linking magnetic microturbulence with suppression of heat conduction in a high-\b{eta} plasma.
发表机构
- University of Oxford（牛津大学）
- Rutherford Appleton Laboratory（鲁瑟福阿普尔顿实验室）
- AWE（英国原子武器研究局）
- University of Chicago（芝加哥大学）
- Gettysburg College（盖茨堡学院）
- Queen’s University Belfast（贝尔法斯特女王大学）
- University of Rochester（罗切斯特大学）
- University of California Berkeley（加州大学伯克利分校）
机构由 AI 辅助整理，请以论文原文为准。
