Heating of braided coronal loops
Heating of braided coronal loops
复制标题
DOI：
10.1051/0004-6361/201117942
复制
发表时间：
2011-11
影响因子：
6.5
通讯作者：
A. Wilmot-Smith;D. Pontin;A. Yeates;G. Hornig
中科院分区：
文献类型：
--
作者：
A. Wilmot-Smith;D. Pontin;A. Yeates;G. Hornig
目标。我们研究了编织磁环的弛豫，以找出通过脚点运动的编织类型如何影响环路的最终加热。方法。以两种不同编织方式的磁环作为初始条件，研究了其后续演化过程。结果。这两个场都经历了一种电阻弛豫，在这种弛豫中，电流片形成并破碎，系统向较低能量的状态演化。在一种情况下，这种松弛是非常有效的电流片填充的体积和均匀加热的回路发生。在另一种情况下，更少的电流片形成，更少的磁能在过程中被释放，导致环路的局部加热。这两种情况，虽然在他们的设置非常相似，可以区分的混合性质的光球驱动器。混合可以通过等离子体流的拓扑熵来测量，这是一个可观察的量。
Aims. We investigate the relaxation of braided magnetic loops in order to find out how the type of braiding via footpoint motions affects resultant heating of the loop. Methods. Two magnetic loops, braided in different ways, are used as initial conditions in resistive MHD simulations and their subsequent evolution is studied. Results. The fields both undergo a resistive relaxation in which current sheets form and fragment and the system evolves towards a state of lower energy. In one case this relaxation is very efficient with current sheets filling the volume and homogeneous heating of the loop occurring. In the other case fewer current sheets develop, less magnetic energy is released in the process and a patchy heating of the loop results. The two cases, although very similar in their setup, can be distinguished by the mixing properties of the photospheric driver. The mixing can be measured by the topological entropy of the plasma flow, an observable quantity.