高能量密度等离子体中磁重联的控制
Control of Magnetic Reconnection in High Energy Density Plasmas
浏览论文内容
中文总结 AI 辅助
本研究通过第三束相对论强度激光注入电子电流丝，在激光驱动等离子体中实现了磁重联的主动控制，可根据激光到达时间加速或抑制磁重联，为聚变等离子体磁能调控及实验室天体物理研究提供新途径。
中文摘要 AI 辅助
磁重联主导着从太阳日冕到聚变等离子体等系统中磁能的爆炸性释放，但在实验室中对其进行控制一直难以实现。本文中，我们展示了在高功率激光驱动等离子体中对磁重联的主动控制，方法是使用第三束相对论强度的激光脉冲，将电子电流丝注入重联系统。两束中等强度的激光驱动碰撞的磁化羽流发生重联，在质子偏转测量中可见，电流片中形成了等离子体团。相对论激光产生的磁场与电流层两侧的极性匹配，根据其到达时间，要么加速电流片的破裂，要么抑制磁重联。在羽流强烈相互作用之前提前到达时，它会构建一个磁压囊，通过通量堆积排斥羽流；在电流片形成后到达时，它会加速电子，将电流丝不稳定性延伸到上游，导致重联磁场快速耗散。该方法为控制聚变等离子体中的磁能流动开辟了途径，并扩大了实验室天体物理学可研究的系统范围。
英文摘要
Magnetic reconnection governs the explosive release of magnetic energy in systems from the solar corona to fusion plasmas, yet controlling it in the laboratory has remained out of reach. Here we demonstrate active control of reconnection in high-power laser-driven plasmas using a third, relativistic-intensity laser pulse that injects filaments of electron current into the reconnecting system. Two moderate-intensity lasers drive colliding magnetized plumes that reconnect, forming plasmoids in the current sheet as seen in proton deflectometry. The relativistic laser generates magnetic fields matching the polarity on either side of the layer, and, depending on its arrival time, either accelerates the breakup of the current sheet or suppresses reconnection. Arriving early, before the plumes strongly interact, it builds a pocket of magnetic pressure that repels them via flux pileup; arriving after the current sheet forms, it accelerates electrons that extend current filamentation instabilities into the upstream, causing rapid dissipation of the reconnecting magnetic field. This approach opens a route to steering magnetic energy flow in fusion plasmas and broadens the range of systems accessible to laboratory astrophysics.
