A multistep implicity scheme for time-dependent 2-dimensional Magnetohydrodynamic flows
A multistep implicity scheme for time-dependent 2-dimensional Magnetohydrodynamic flows
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DOI：
10.1016/0021-9991(89)90242-8
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发表时间：
1989-10
影响因子：
4.1
通讯作者：
Y. Hu
中科院分区：
文献类型：
--
作者：
Y. Hu
众所周知，许多太阳现象发生在活动区或活动区附近，这些活动区的磁场很强，对等离子体的支持、加热和加速起着主导作用。在这种情况下，如果采用显式方法，时间步长将受到CFL条件的严格限制，且计算时间较长，存在数值不稳定性。此外，为了限制计算域的大小，对必须引入的人工边界的不适当处理往往会导致非物理反射。提出了一种求解含时二维磁流体力学方程的隐式算法，它由离散控制方程的多步隐式格式和规定人工边界条件的投影特征线法组成。该算法通过一个物理问题来说明，该问题涉及静态大气对从光球层下方出现的相反极性磁通量的动态响应。给出了该格式和投影特征线法的稳定性判据。
It is well known that many solar phenomena take place in or near active regions where the magnetic fields are so strong as to play a predominant role in supporting, heating, and accelerating the plasma. The time step would be severely restricted by the CFL condition and a long time computation would be subjected to numerical instability if an explicit method were adopted in these cases. In addition, improper treatment of the artificial boundaries one has to introduce in order to limit the size of the computational domain often leads to unphysical reflections. An implicit algorithm for solving time-dependent, 2-dimensional magnetohydrodynamic equations is presented which consists of a multistep implicit scheme for discretizing the governing equations and the projected characteristic method for stipulating artificial boundary conditions. The algorithm is illustrated by a physical problem concerning the dynamical response of the static atmosphere to a magnetic flux emergence of opposite polarity from below the photosphere. The stability criteria are given for both the scheme and the projected characteristic method.