| 磁层顶压缩事件的磁场分析 |
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| 引用本文： | 沈晓阳,陈鸿飞.磁层顶压缩事件的磁场分析[J].地球物理学报,2006,49(2):321-327. |
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| 作者姓名： | 沈晓阳 陈鸿飞 |
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| 作者单位： | 北京大学地球与空间科学学院空间物理与应用技术研究所,北京,100871 |
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| 基金项目： | 北京市教委共建项目（XK100010404）和国家杰出青年基金（40425004）资助. |
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| 摘 要： | 向日面磁层顶在平静太阳风条件下，处于10RE（RE为地球半径）左右．但在异常的太阳风条件下，即南向行星际磁场很强和（或）太阳风的动压很大时，会被压缩，甚至到达同步轨道附近．集中分析2001年4月11日的磁暴事件，研究当磁层顶发生强烈压缩以后。在地球空间和地面上产生的磁场影响．磁层顶位形选取Shue（1998）模型计算．当把计算结果与GOESl0卫星的观测数据对比时发现：磁层顶在强的太阳风条件下的确会被压缩到同步轨道以内．Shue（1998）模型的预测基本正确，通常的漏报可能是由于预报的位置误差所致．实际磁层顶电流片的位置和强度与我们假设的理想磁层顶间断面计算结果基本吻合．在分析大磁暴过程时，磁层顶压缩使磁层顶电流对于中低纬度地磁场扰动有突出的贡献，在2001年4月事件中，这个贡献可以大于50nT，占主相的1／6左右．这一贡献可以使Dst指数产生相应的误差．
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| 关 键 词： | 磁层顶压缩 磁层顶电流 CF电流 地磁扰动 磁暴 |
| 文章编号： | 0001-5733（2006）02-0321-07 |
| 收稿时间： | 2005-03-28 |
| 修稿时间： | 2005-03-282005-12-01 |
Analysis of a compressive event in the magnetopause |
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| SHEN Xiao-Yang,CHEN Hong-Fei.Analysis of a compressive event in the magnetopause[J].Chinese Journal of Geophysics,2006,49(2):321-327. |
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| Authors: | SHEN Xiao-Yang CHEN Hong-Fei |
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| Institution: | Institute of Space Physics and Applied Technology, School of Earth and Space Sciences, Peking University, Beijing 100871, China |
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| Abstract: | Under the quiet solar wind condition, the dayside magnetopause is at about 10R_E from the center of the Earth. But under the extreme solar wind condition, such as large southward Interplanetary Magnetic Field (IMF-B_z) and/or large solar wind dynamic pressure (D_P), the magnetopause will be compressed even inside the geosynchronous orbit. We analyze the magnetic storm on April 11, 2001 to investigate how the compression of the magnetopause would influence the magnetic field in the geospace and on the ground when it was strongly compressed. We choose the model of Shue (1998) to predict the position and shape of the magnetopause. By comparison of the calculation with the observation of the GOES10 satellite on the geosynchronous orbit, we find that under the extreme solar wind condition, the magnetopause does move inside the geosynchronous orbit. Shue (1998) model is approximately correct, and some faults may be due to its errors in position. The location and intensity of the CF-current on the magnetopause are almost same as the results from the model of the ideal discontinuous surface. For large magnetic storms, the compression of the magnetopause can cause obvious magnetic field disturbances on the ground at middle and low latitudes. In the event mentioned above, this contribution can be larger than 50nT, which is almost 1/6 of the main phase. So, the compression of the magnetopause may generate considerable error in Dst index. |
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| Keywords: | Magnetopause compression Magnetopause current CF-current Geomagnetic disturbances Magnetic storm |
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