3-D magnetic field and current system in the heliosphere
3-D magnetic field and current system in the heliosphere
复制标题
日光层中的 3-D 磁场和电流系统
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
Takashi Tanaka
中科院分区：
文献类型：
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作者：
H. Washimi;Takashi Tanaka
本文用三维磁流体动力学模拟方法模拟了太阳风等离子体与星际介质相互作用产生的全球磁场和电流系统。在我们的模拟中清楚地确定了终端激波、日球顶和外激波。在日鞘中，环向磁场随着离太阳的距离而增大。磁场在日鞘上游区域迅速增加，并在终端激波和日顶之间达到最大值。因此，在日鞘中形成了壳型磁壁。由于磁壁的存在，径向膨胀的太阳风等离子体在除赤道区域外的所有纬度上都向尾部方向变化。只有赤道盘状等离子体流被发现通过赤道周围的弱磁场区延伸到日球顶。模拟中发现了维持日球层环形磁场的两种全球电流环，并考察了11年太阳活动周期磁极变化对日球层环形磁场的影响。结果表明，日鞘环向磁场的极性在每个太阳活动周都发生变化。因此，日鞘被发现是由这样的磁化等离子体泡。发现中性片以复杂的形式在三维日鞘中的这些磁化等离子体泡之间延伸。磁压效应对日鞘等离子体结构的影响也进行了研究。
In this paper a global system of the magnetic field and current from the interaction of the solar wind plasma and the interstellar medium is modeled using a 3-D MHD simulation. The terminal shock, the heliopause and the outer shock are clearly determined in our simulation. In the heliosheath the toroidal magnetic field is found to increase with the distance from the sun. The magnetic field increases rapidly in the upstream region of the heliosheath and becomes maximum between the terminal shock and the heliopause. Hence a shell-type magnetic wall is found to be formed in the heliosheath. Because of this magnetic wall the radially expanding solar wind plasma changes its direction tailward in all latitudes except the equatorial region. Only the equatorial disk-like plasma flow is found to extend to the heliopause through the weak magnetic-field region around the equator. Two kinds of global current loops which sustain the toroidal magnetic field in the heliosphere are found in our simulation.The influence of the 11-year solar cycle variation of the magnetic polarity is also examined. It is found that the polarity of the toroidal magnetic field in the heliosheath switches at every solar cycle change. Hence the heliosheath is found to consist of such magnetized plasma bubbles. The neutral sheets are found to extend between such magnetized plasma bubbles in the 3-D heliosheath in a complicated form. The magnetic-pressure effect on the heliosheath plasma structure is also examined.