MHD STAGNATION-POINT FLOWS AT A CURRENT SHEET INCLUDING VISCOUS AND RESISTIVE EFFECTS - GENERAL 2-DIMENSIONAL SOLUTIONS
MHD STAGNATION-POINT FLOWS AT A CURRENT SHEET INCLUDING VISCOUS AND RESISTIVE EFFECTS - GENERAL 2-DIMENSIONAL SOLUTIONS
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DOI：
10.1017/s0022377800015361
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发表时间：
1990-12-01
影响因子：
2.5
通讯作者：
SONNERUP, BUO
中科院分区：
文献类型：
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作者：
PHAN, TD;SONNERUP, BUO
提出了分离两个碰撞等离子体的电流片处的二维稳态不可压缩驻点流的精确解。 他们描述了电阻场湮灭（零重联）的过程，其中每个等离子体中的磁场严格平行于电流片，但其两侧可能具有不同的大小和方向。 (x,y) 平面中朝向位于 x = 0 处的当前片的流动可以具有任意的入射角以及与驻点的任意量的发散或会聚。 我们找到了等离子体速度和磁场解的最一般形式。 对于流和场的 z 分量，找到 y 中截断幂级数形式的解。 本研究中获得的案例包含 Parker、Sonnerup & Priest、Gratton 等人获得的解决方案。 Besser、Biernat 和 Rijnbeek 作为特例。 研究了粘度在确定流和场配置中的作用。 当两个碰撞等离子体具有相同的粘度和密度时，表明粘性效应通常仅在粘性雷诺数等于或小于1的强发散或会聚粘性流中才重要。 对于天体物理应用，粘性雷诺数通常很高，并且粘性对具有相似特性的等离子体相互作用的影响很小。 还提出了涉及不同性质等离子体的驻点流动问题的公式。 显示了此类流程的示例案例。 最后，简要讨论了这项研究结果在地球磁层顶的可能应用。
Exact solutions are presented of two-dimensional steady-state incompressible stagnation point flows at a current sheet separating two colliding plasmas. They describe the process of resistive field annihilation (zero reconnection) where the magnetic field in each plasma is strictly parallel to the current sheet, but may have different magnitudes and direction on its two sides. The flow in the (x,y) plane toward the current sheet, located at x = 0, may have an arbitrary angle of incidence and an arbitrary amount of divergence from or convergence towards the stagnation point. We find the most general form of the solution for the plasma velocity and for the magnetic field. For the z components of the flow and field, solutions in the form of truncating power series in y are found. The cases obtained in this study contain the solutions obtained by Parker, Sonnerup & Priest, Gratton et al. and Besser, Biernat & Rijnbeek as special cases. The role of viscosity in determining the flow and field configurations is examined. When the two colliding plasmas have the same viscosity and density, it is shown that viscous effects usually are important only in strongly divergent or convergent viscous flows with viscous Reynolds number of the order of unity or smaller. For astrophysical applications the viscous Reynolds number is usually high and the effects of viscosity on the interaction of plasmas of similar properties are small. The formulation of the stagnation-point flow problem involving plasmas of different properties is also presented. Sample cases of such flows are shown. Finally, a possible application of the results from this study to the earth's magnetopause is discussed briefly.