Department of Physics/Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Phys Rev Lett. 2010 Jun 25;104(25):255004. doi: 10.1103/PhysRevLett.104.255004.
Magnetic reconnection is a fundamental process in plasmas that results in the often explosive release of stored magnetic energy, but the trigger for its onset is not well understood. We explore this trigger for fast reconnection in toroidal experiments using a magnetic x-type geometry in the strong guide-field regime. We find that the onset occurs asymmetrically: the reconnection begins on one side of the torus and propagates around approximately at the Alfvén speed. The fast reconnection occurs only in the presence of a global plasma mode, which breaks the axisymmetry and enables the current at the x line to decrease sharply. A simple semiempirical model is used to describe the onset's growth rate.
磁重联是等离子体中的一个基本过程，导致储存的磁能经常发生爆炸释放，但磁重联的触发机制还不是很清楚。我们在强引导场条件下的环形容器实验中使用磁场 X 型几何结构来探索这种快速磁重联的触发机制。我们发现，触发过程是不对称的：重联首先在环形容器的一侧开始，并以大约阿尔文速度传播。只有在存在全局等离子体模式的情况下才会发生快速磁重联，这种模式打破了轴对称性，并使 X 线的电流急剧下降。我们使用一个简单的半经验模型来描述触发机制的增长率。
