The effect of erosion on the solar wind stand-off distance at Mercury
The effect of erosion on the solar wind stand-off distance at Mercury
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DOI：
10.1029/ja084ia05p02076
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发表时间：
1979-05
影响因子：
--
通讯作者：
J. Slavin;R. Holzer
中科院分区：
文献类型：
--
作者：
J. Slavin;R. Holzer
最近的研究提供了向阳面磁场重联对地球前向磁层顶位置影响的定量测量。通过将这些地面观测结果换算到水星，预测平均太阳风动压条件下的平均太阳风对峙距离将从其“基态”位置向内0.2- 0.7 R/sub m/。此外，预计磁层顶将被侵蚀和/或压缩到水星表面的0.2R/sub m/的大部分时间。经验公式推导出地球的磁层被用来确定太阳风的对峙距离和太阳风的动态压力的水手10号遇到水星的磁层。结果表明，对于第一次相遇，当行星际磁场通常是向南的，并且在磁层内观测到亚暴信号时，由边界穿越推断的平均对峙距离为1.5R/sub m/（P/sub s/w=6.0 × 10/sup 8/dynes/cm/sup 2/）。在最后一次遭遇时，水手10号的磁力计没有观测到IMF有明显的向南分量，也没有明显的亚暴活动。对于这次遭遇，推断的平均间隔距离为1.9R/sub m/，与更接近地球类型的磁层内磁通量传输的预期效应一致。根据观测到的弓形激波和磁层顶位置，计算得到了6 +- 2 × 10/sup ~（22）/ G-cm/sup ~（3/）的偶极矩。最后，简要讨论了磁通量传输在水星太阳风-磁层-大气-地表相互作用中的重要性。«少
Recent studies have provided quantitative measurements of the effect of dayside magnetic reconnection on the position of the earth's forward magnetopause. By scaling these terrestrial observations to Mercury, it is predicted that the mean solar wind stand-off distance for average solar wind dynamic pressure conditions will be 0.2--0.7 R/sub m/ inward from its 'ground state' position. Furthermore, it is expected that the magnetopause will be eroded and/or compressed to within 0.2R/sub m/ of Mercury's surface a significant portion of the time. Empirical formulae derived for the earth's magnetosphere are used to determine both solar wind stand-off distances and solar wind dynamic pressures for the two Mariner 10 encounters with Mercury's magnetosphere. It is found that for the first encounter when the interplanetary magnetic field was often southward and substorm signatures are observed inside the magnetosphere, the mean stand-off distance inferred from the boundary crossings is 1.5R/sub m/(for P/sub s/w=6.0 x 10/sup 8/dynes/cm/sup 2/). At the time of the final encounter, the Mariner 10 magnetometer observed no significant southward component in the IMF and no substorm activity was evident. For this encounter, the mean inferred stand-off distance is 1.9R/sub m/ consistent with the expected effects of magnetic flux transfer within amore » terrestrial-type magnetosphere. A dipole moment of 6 +- 2 x 10/sup 22/ G-cm/sup 3/ is calculated from the observed bow shock and magnetopause positions. Finally, the importance of magnetic flux transfer in the solar wind-magnetospher-atmosphere-surface interaction at Mercury is briefly discussed.« less