Fiksel G, Fox W, Bhattacharjee A, Barnak D H, Chang P-Y, Germaschewski K, Hu S X, Nilson P M
Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA and Fusion Science Center for Extreme States of Matter, University of Rochester, Rochester, New York 14623, USA.
Department of Astrophysical Sciences and Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA.
Phys Rev Lett. 2014 Sep 5;113(10):105003. doi: 10.1103/PhysRevLett.113.105003. Epub 2014 Sep 4.
Observations of magnetic reconnection between colliding plumes of magnetized laser-produced plasma are presented. Two counterpropagating plasma flows are created by irradiating oppositely placed plastic (CH) targets with 1.8-kJ, 2-ns laser beams on the Omega EP Laser System. The interaction region between the plumes is prefilled with a low-density background plasma and magnetized by an externally applied magnetic field, imposed perpendicular to the plasma flow, and initialized with an X-type null point geometry with B=0 at the midplane and B=8 T at the targets. The counterflowing plumes sweep up and compress the background plasma and the magnetic field into a pair of magnetized ribbons, which collide, stagnate, and reconnect at the midplane, allowing the first detailed observations of a stretched current sheet in laser-driven reconnection experiments. The dynamics of current sheet formation are in good agreement with first-principles particle-in-cell simulations that model the experiments.
本文展示了对磁化激光产生等离子体的碰撞羽流之间磁重联的观测结果。通过在欧米伽EP激光系统上用1.8千焦、2纳秒的激光束照射相对放置的塑料（CH）靶，产生了两个反向传播的等离子体流。羽流之间的相互作用区域预先充满了低密度背景等离子体，并由垂直于等离子体流施加的外部磁场磁化，在中平面处初始化为X型零点几何结构，B = 0，在靶处B = 8 T。反向流动的羽流将背景等离子体和磁场扫起并压缩成一对磁化带，它们在中平面碰撞、停滞并重新连接，从而在激光驱动的重联实验中首次对拉伸电流片进行了详细观测。电流片形成的动力学与模拟实验的第一性原理粒子模拟结果高度吻合。
