A Three-Dimensional Asymmetric Magnetopause Model

作     者：R. L. Lin1,2 X. X. Zhang3 S. Q. Liu1 Y. L. Wang4 J. C. Gong1 1Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing, China 2Graduate University of Chinese Academy of Sciences, Beijing, China 3 National Center for Space Weather, China Meteorological Administration, Beijing, China 4 NASA/Goddard Space Flight Center, Greenbelt, Maryland, USA 

会议名称：《第27届中国气象学会年会空间天气自主资料应用与模式集成分会场》

会议日期：2010年

学科分类：070802[理学-空间物理学] 07[理学] 0708[理学-地球物理学] 

基　　金：国家自然科学基金(批准号:40774079和40890160) 国家高技术研究发展计划(863)项目(批准号:2007AA12Z314) 公益性行业专项(批准号:GYHY200806024)~~ 

关 键 词：Magnetopause model magnetopause size and shape solar wind dynamic pressure interplanetary magnetic field Bz indentation 

摘      要：A new three-dimensional asymmetric magnetopause model has been developed for corrected GSM coordinates and parameterized by the solar wind dynamic and magnetic pressures (Pd+Pm), the interplanetary magnetic field (IMF) Bz, and the dipole tilt angle. Based on the magnetopause crossings from Geotail, IMP8, Interball, TC1, THEMIS, Wind, Cluster, Polar, LANL, GOES and Hawkeye, and the corresponding upstream solar wind parameters from ACE, Wind or OMNI, this model is constructed by the Levenberg-Marquardt method for nonlinear multi-parameter fitting step by step over the divided regions. The asymmetries of the magnetopause and the indentations near the cusps are appropriately described in this new model. In addition, the saturation effect of IMF Bz on the subsolar distance and the extrapolation for the distant tail magnetopause are also considered. Based on this model, the power law index for the subsolar distance versus Pd+Pm is a bit less than -1/6, the northward IMF Bz almost does not influence the magnetopause, and the dipole tilt angle is very important to the north-south asymmetry and the location of indentations. In comparison with the previous empirical magnetopause models based on our database, the new model improves prediction capability to describe the three-dimensional structure of the magnetopause. It isshown that this new model can be used to quantitatively study how Pd+Pm compresses the magnetopause, how the southward IMF Bz erodes the magnetopause, and how the dipole tilt angle influences the north-south asymmetry and the indentations.