火星磁层顶形成和变化的理论研究  

Theoretic Study on Formation and Variation of MagnetoDause of Planet Mars

作　　者：史建魁[1] 程征伟[1] 王胜国[1,2] Zhang T L 刘振兴[1] 

机构地区：[1]中国科学院空间科学与应用研究中心空间天气学国家重点实验室,北京100190 [2]北京应用气象研究所,北京100081 [3]Space Research Institute, Austrian Academy of Sciences, 8042 Graz, Austria

出　　处：《空间科学学报》2011年第5期567-572,共6页Chinese Journal of Space Science

基　　金：国家自然科学基金项目(41074114,40921063);国家重点实验室专项基金项目;中国科学院创新方向性项目(KJCX2-YW-T13-3)共同资助

摘　　要：考虑太阳风动压与行星电离层中的带电粒子热压及磁压之和平衡,建立了有大气(电离层)的行星磁层顶形成的理论模型,结合卫星对火星的观测数据,对子午面内向日侧火星磁层顶位形进行了数值计算和分析,研究了火星磁层顶位形及其与太阳风动压之间的变化关系.结果认为,火星磁层顶位形与地球磁层顶相似.太阳风动压越大,火星磁层顶越靠近火星;太阳风动压越弱,火星磁层顶越远离火星.根据火星内秉磁矩从古到今逐渐减小的观点,探索了大尺度磁场(内禀磁矩)对火星磁层顶的贡献作用,结果认为大尺度磁场越强,火星磁层顶越远离行星.这对于进一步研究火星磁层的长期演化以及其他行星磁层的位形变化都具有重要的意义.It is known that Mars has no intrinsic magnetic field according to the observation, and it has an induced magnetosphere with a formation different from the Earth＇s. In this paper, to consider the balance between solar wind dynamic pressure and the planetary ionospheric charged particle pressure companying with a weak intrinsic magnetic field pressure, a model for formation of planet Mars magnetopause is established. According to the satellite observation, configuration of the dayside Martian magnetopause and its variation in the meridian planes are studied with the model. The results show that the configuration of the dayside Martian magnetopause has some similarities to the geo-magnetopause. The stronger the solar wind dynamic pressure is, the closer the Martian magnetopause to the Mars surface will be. The weaker the solar wind dynamic pressure is, the farther the Martian magnetopause to the Mars surface will be. According to the view that the Martian intrinsic magnetic moment is reducing from ancient times to the present and it would be reversed, the role of the large scale magnetic field to the Martian magnetopause is studied with an assumed intrinsic magnetic moment. The results show that the stronger the intrinsic magnetic moment was, the further the Martian magnetopause to the Mars surface would be. The weaker the intrinsic magnetic moment was, the closer the Martian magnetopause to the Mars surface would be. These results are significant not only to study the long term variation of the Martian magnetosphere, but also to study the configuration of magnetopause in general planet.

关 键 词：火星 磁层顶 位形和变化 

分 类 号：P353[天文地球—空间物理学]