Observations of a Field-Aligned Ion/Ion-Beam Instability in a Magnetized Laboratory Plasma
Observations of a Field-Aligned Ion/Ion-Beam Instability in a Magnetized Laboratory Plasma
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DOI：
10.1063/1.5017637
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发表时间：
2017-11
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通讯作者：
P. Heuer;M. Weidl;R. Dorst;D. Schaeffer;A. Bondarenko;S. K. Tripathi;B. V. Compernolle;S. Vincena-S.-Vin
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作者：
P. Heuer;M. Weidl;R. Dorst;D. Schaeffer;A. Bondarenko;S. K. Tripathi;B. V. Compernolle;S. Vincena-S.-Vin
超强离子和平行于背景磁场的环境等离子体之间的无碰撞耦合是由一组电磁离子/离子束不稳定性（包括共振右手不稳定性（RHI））介导的。为了研究这种耦合及其在平行激波形成中的作用，加州大学洛杉矶分校的一个新实验配置利用高能和高重复率激光器在大型等离子体装置 (LAPD) 的环境等离子体内产生超 Alfv\'{e}nic 场对准碎片等离子体。我们使用时间分辨荧光单色仪和朗缪尔探针阵列来表征激光等离子体速度分布和密度。观察到碎片离子具有足够的超强电性和密度，足以激发 RHI。使用磁通量探头进行的测量显示出与激光目标附近 RHI 的激励一致的右旋圆偏振频率啁啾。我们将测量结果与实验的二维混合模拟进行了比较。
Collisionless coupling between super Alfv\'{e}nic ions and an ambient plasma parallel to a background magnetic field is mediated by a set of electromagnetic ion/ion-beam instabilities including the resonant right hand instability (RHI). To study this coupling and its role in parallel shock formation, a new experimental configuration at the University of California, Los Angeles utilizes high-energy and high-repetition-rate lasers to create a super-Alfv\'{e}nic field-aligned debris plasma within an ambient plasma in the Large Plasma Device (LAPD). We used a time-resolved fluorescence monochromator and an array of Langmuir probes to characterize the laser plasma velocity distribution and density. The debris ions were observed to be sufficiently super-Alfv\'{e}nic and dense to excite the RHI. Measurements with magnetic flux probes exhibited a right-hand circularly polarized frequency chirp consistent with the excitation of the RHI near the laser target. We compared measurements to 2D hybrid simulations of the experiment.