Observation of collisionless shocks in a large current‐free laboratory plasma
Observation of collisionless shocks in a large current‐free laboratory plasma
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大无电流实验室等离子体中无碰撞冲击的观察
DOI：
10.1002/2014gl061820
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发表时间：
2014
影响因子：
5.2
通讯作者：
P. Pribyl
中科院分区：
文献类型：
--
作者：
C. Niemann;W. Gekelman;C. Constantin;E. Everson;D. Schaeffer;A. Bondarenko;S. E. Clark;D. Winske;S. Vincena;B. V. Compernolle;P. Pribyl
我们报告了在无电流的实验室等离子体中通过激光驱动的磁性活塞对磁化无碰撞冲击波的形成和结构的首次测量。这类新的实验结合了高能激光系统和大型磁化等离子体，通过无碰撞耦合将能量从激光等离子体羽流转移到周围的离子，直到自维持的MA 122磁声冲击与活塞分离。周围的等离子体是高度磁化的，没有电流，并且足够大（17 m × 0.6 m）以支持阿尔文波。对激波结构和演化的磁场测量与二维混合模拟一致，该模拟显示碎片和环境离子之间的拉莫尔耦合以及反射离子的存在，这提供了耗散。测得的冲击波形成时间证实了计算工作的预测。
We report the first measurements of the formation and structure of a magnetized collisionless shock by a laser‐driven magnetic piston in a current‐free laboratory plasma. This new class of experiments combines a high‐energy laser system and a large magnetized plasma to transfer energy from a laser plasma plume to the ambient ions through collisionless coupling, until a self‐sustained MA∼ 2 magnetosonic shock separates from the piston. The ambient plasma is highly magnetized, current free, and large enough (17 m × 0.6 m) to support Alfvén waves. Magnetic field measurements of the structure and evolution of the shock are consistent with two‐dimensional hybrid simulations, which show Larmor coupling between the debris and ambient ions and the presence of reflected ions, which provide the dissipation. The measured shock formation time confirms predictions from computational work.