Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Centre Lasers Intenses et Applications, University of Bordeaux, CNRS, CEA, 33405 Talence, France.
Phys Rev Lett. 2019 Aug 2;123(5):055002. doi: 10.1103/PhysRevLett.123.055002.
Collisionless shocks are ubiquitous in the Universe as a consequence of supersonic plasma flows sweeping through interstellar and intergalactic media. These shocks are the cause of many observed astrophysical phenomena, but details of shock structure and behavior remain controversial because of the lack of ways to study them experimentally. Laboratory experiments reported here, with astrophysically relevant plasma parameters, demonstrate for the first time the formation of a quasiperpendicular magnetized collisionless shock. In the upstream it is fringed by a filamented turbulent region, a rudiment for a secondary Weibel-driven shock. This turbulent structure is found responsible for electron acceleration to energies exceeding the average energy by two orders of magnitude.
无碰撞激波是宇宙中普遍存在的现象，是超音速等离子体流穿过星际和星系际介质的结果。这些激波是许多观测到的天体物理现象的原因，但由于缺乏实验研究的方法，激波结构和行为的细节仍然存在争议。本文报道的具有天体物理相关等离子体参数的实验室实验首次证明了准垂直磁化无碰撞激波的形成。在上游，它被一个丝状的湍流区域所包围，这是二次 Weibel 驱动激波的雏形。这种湍流结构被发现是将电子加速到超过平均能量两个数量级的能量的原因。
