地球磁场对太阳风扰动响应的研究

Research of Geospace Magnetic Field Response to the Solar Wind Disturbances

分别对行星际激波、太阳风动压增大事件和减小事件的地球磁场响应进行了比较.分析结果表明,同步轨道磁场对太阳风扰动在向阳面产生较强的正响应,在背阳面响应较弱且有时会出现负响应,地磁指数SYM-H对太阳风扰动的响应为正响应.同时还得出,向阳侧同步轨道磁场响应幅度d B_z与地磁指数响应幅度d SYM-H、上下游动压均方差均具有较好的相关性.地磁指数响应幅度与同步轨道磁场响应幅度相关关系在激波和动压增大事件中具有一致性,动压减小事件出现明显差异,这说明激波和动压增大事件在影响地球磁场方面具有某种共性.

The goespace magnetic field response to the solar wind disturbances including interplanetary shocks,solar wind dynamic pressure increase and decrease is analyzed comparatively.The geosynchronous magnetic field has positive response to all the disturbances strongly near the noon meridian,and has positive response in the nightside of the magnetosphere weakly.However negative responses were sometimes observed in the nightside.From our results,the geomagnetic index SYM-H always shows positive response to the disturbances of solar wind.The amplitude of geosynchronous response d B_z could be determined by the square root of the solar wind dynamic pressure near the noon meridian with good correlation the same as the geomagnetic indices.The d B_z at the geosynchronous orbit near local noon and the amplitude of sudden impulses（d SYM-H） on the ground are highly correlated under the circumstances action of IP shock or solar wind dynamic pressure increase,differentiating from the dynamic pressure decrease distinctly.It is shown that the IP shocks have some commonness with the solar wind dynamic pressure increase in affecting on the geospace magnetic field.