Increasing exposure of geosynchronous orbit in solar wind due to decay of Earth's dipole field
Increasing exposure of geosynchronous orbit in solar wind due to decay of Earth's dipole field
复制标题
由于地球偶极子场的衰减，太阳风中地球同步轨道的暴露增加
DOI：
10.1002/2014ja020549
复制
发表时间：
2014
影响因子：
2.8
通讯作者：
Han X. H.
中科院分区：
文献类型：
--
作者：
Zhong J.;Wan W. X.;Wei Y.;Fu S. Y.;Jiao W. X.;Rong Z. J.;Chai L. H.;Han X. H.
在过去的1.5个世纪里，地球的偶极矩一直在衰减。因此，磁层一直在缩小，地球同步磁层顶穿越的机会一直在增加。定量地评估了由于偶极矩衰减和太阳风条件的变化而引起的地球同步轨道在太阳风中暴露量的增加，并研究了如果这种衰减持续几个世纪的可能情况。结果表明，假设地球偶极矩以目前的速率线性减小，平均太阳磁层顶距离每世纪将向地球移动约0.3RE。在行星际磁场向北（向南）的情况下，地球同步磁层顶穿越所需的最小太阳风动压在未来100年内将降低~4 nPa（2 nPa）。在正常的太阳风条件下，地球同步轨道的正午区域将在未来几个世纪内暴露在太阳风中。这些结果表明，地磁场的长期变化对我们了解空间气候至关重要。
The Earth's dipole moment has been decaying over the past 1.5 centuries. The magnetosphere thus has been shrinking and the chance of geosynchronous magnetopause crossings has been increasing. We quantitatively evaluate the increasing exposure of geosynchronous orbit in the solar wind caused by the decay of dipole moment and the variation of solar wind condition and study the possible situation if such decay persists for several more centuries. The results show that the average subsolar magnetopause distance would move earthward by ~0.3 RE per century, assuming the linear decreasing of the Earth's dipole moment at present rate. The minimum solar wind dynamic pressure required for geosynchronous magnetopause crossings will decrease by ~4 nPa (2 nPa) in the next 100 years under northward (southward) interplanetary magnetic field. Under normal solar wind conditions, the noon region of the geosynchronous orbit will be exposed to the solar wind in the next few centuries. These results suggest that the secular variations of geomagnetic field are of paramount importance for our understanding of space climate.