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摘要
An outstanding flare on 20 January 2005 was accompanied by a coronal mass ejection which arrived at the magnetopause at similar to 1712 UT, 21 January, and produced a strong compression-pressure pulse. Enhanced magnetospheric activity was stimulated. The associated development between <1800 UT and >02.19 UT on 21-22 January, 2005 of a ring current disturbance in energetic neutral atom (ENA) data, recorded aboard both the Double Star and the IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) spacecraft, is described. A magnetic storm from similar to 1712 UT, 21 January, reached minimum Dst = similar to-101 nT at similar to 0600 UT, 22 January, and its recovery phase endured until 27 January. ENA data indicate that the ring current experienced a deep injection of H(+) and O(+) ions at similar to 1830 UT when IMF Bz was oriented southward. At this time, the ring current was strongly asymmetric, although later it became more symmetric. Bz turned northward at 1946 UT. From similar to 0224 to similar to 0612 UT on 22 January, Bz fluctuated such that it intermittently pointed southward (+/- 10 nT). The moderate but extended response of the geomagnetosphere to the strong pressure pulse is explained by a slow evolution in the orientation of Bz under conditions of enhanced plasma sheet density. Modeling of dynamical parameters that represent various current systems that contributed to Dst revealed their individual characteristics. The changing geomagnetic field was also modeled. Comparisons with ENA data show that early asymmetric enhancements recorded in hydrogen and oxygen were accompanied by intensified external current systems that produced a magnetic field related compression of the magnetosphere. The gradual reduction in ring current asymmetry was complemented by the largely symmetrical configuration displayed by the corresponding, still intensified, modeled magnetic field.
- 出版日期2010-8-14
- 单位中国科学院国家空间科学中心
