arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1102.2351astro-ph.SRphysics.plasm-ph
收藏

在单个三维磁零点处的稳态重联

Steady state reconnection at a single 3D magnetic null point

K. Galsgaard, D. I. Pontin

摘要:

通过沿相反方向平流输送脊柱轴的相反足点,系统地对旋转对称的3D磁零点施加应力。该应力最终集中在零点附近,形成局部电流片,通过该局部电流片发生磁重联。我们的目的是寻找一个稳定的状态演变的电流片动力学,这可能提供系统的各种特征参数的标度关系。其次,通过数值求解非理想MHD方程的笛卡尔域的演变。零点嵌入在一个初始恒定的密度和温度等离子体。结果表明,连续剪切驱动可以在三维零点处建立准稳态重联过程。似乎不太可能实现真正的稳定状态,因为当前层倾向于增长,直到受到计算域的几何形状和施加的驱动轮廓的限制。然而,特征量之间的比率在一段时间后明显地稳定到稳定值,因此演化是准稳定的。实验显示了一些标度关系,但它们没有提供一个明确的共识,延伸到较低的磁电阻率或更快的驱动速度。需要更多的调查,以充分澄清在磁零点的电流片的属性。

英文摘要:

To systematically stress a rotationally symmetric 3D magnetic null point by advecting the opposite footpoints of the spine axis in opposite directions. This stress eventually concentrates in the vicinity of the null point forming a local current sheet through which magnetic reconnection takes place. The aim is to look for a steady state evolution of the current sheet dynamics which may provide scaling relations for various characteristic parameters of the system. The evolution is followed by solving numerically the non-ideal MHD equations in a Cartesian domain. The null point is embedded in an initially constant density and temperature plasma. It is shown that a quasi-steady reconnection process can be set up at a 3D null by continuous shear driving. It appears that a true steady state in unlikely to be realised as the current layer tends to grow until restricted by the geometry of the computational domain and imposed driving profile. However, ratios between characteristic quantities clearly settle after some time to stable values -- so that the evolution is quasi-steady. The experiments show a number of scaling relations, but they do not provide a clear consensus for extending to lower magnetic resistivity or faster driving velocities. More investigations are needed to fully clarify the properties of current sheets at magnetic null points.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑