Counter effects of meridional flows and magnetic fields in stationary axisymmetric self-gravitating barotropes under the ideal MHD approximation : Clear examples - toroidal configurations
Counter effects of meridional flows and magnetic fields in stationary axisymmetric self-gravitating barotropes under the ideal MHD approximation : Clear examples - toroidal configurations
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理想 MHD 近似下静止轴对称自重力正压线中经向流和磁场的反作用：清晰的例子 - 环形配置
DOI：
10.1093/mnras/stt275
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Sj. Yoshida & Y. Eriguchi
中科院分区：
文献类型：
--
作者：
K. Fujisawa;R. Takahashi;Sj. Yoshida & Y. Eriguchi
在理想磁流体动力学(MHD)近似下，从控制具有子午流的轴对称磁化自重正压物体定态的基本方程的可积性条件出发，得到了电流密度和涡度的一般形式。从这类天体的定常条件方程可以看出，子午流和极向磁场的存在对内部结构的作用是相反的。在牛顿引力框架下，通过中心点质量周围的经向流和极向磁场这两个物理量的定态结构，可以清楚地看到这两个物理量的不同作用，因为这两个物理量的影响对环状系统的影响比对球星的放大。经向流使结构更加致密，即环的宽度变薄，而极向磁场则容易使密度等值线沿一定方向拉长。因此，在理想的磁流体近似下，内部流动和磁场的同时存在，就好像在静止的气体物体内部和周围没有这种不同的作用，例如在理想MHD近似下，围绕中心致密物体内部运动的轴对称磁化环状物体，尽管这两个量可能存在于真实系统中。
We obtain the general forms for the current density and the vorticity from the integrability conditions of the basic equations which governthe stationary states of axisymmetric magnetized self-gravitating barotropic objects with meridional flows under the ideal magnetohydrodynamics (MHD) approximation. As seen from the stationary condition equations for such bodies, the presence of the meridional flows and that of the poloidal magnetic fields act oppositely on the internal structures.The different actions of these two physical quantities, the meridional flows and the poloidal magnetic fields, could be clearly seen through stationary structures of thetoroidalgaseous configurations around central point masses in the framework of Newtonian gravity because the effects of the two physical quantities can be seen in an amplified way for toroidal systems compared to those for spheroidal stars. The meridional flows make the structures more compact, i.e. the widths of toroids thinner, while the poloidal magnetic fields are apt to elongate the density contours in a certain direction depending on the situation. Therefore, the simultaneous presence of the internal flows and the magnetic fields would work as if there were no such different actions within and around the stationary gaseous objects such as axisymmetric magnetized toroids with internal motions around central compact objects under the ideal MHD approximation, although these two quantities might exist in real systems.