3D STRUCTURE AND MAGNETIC TOPOLOGY OF FLUX TRANSFER EVENTS AT THE MAGNETOPAUSE: FIRST IN SITU OBSRVATIONS Zuyin Pu1([email protected]), Jun Zhong1, and co-authors
1School of Earth and Space Sciences, Peking University, 100871 Beijing, China
Flux transfer events (FTEs) at the magnetopause (MP) create channels for transfer of solar wind energy and plasma into geospace. In spite of many years of research, the 3D structure and magnetic field topology of FTEs are still largely unknown. This work provides first in situ measurements in these aspects. (i) On 14 June 2007, four THEMIS spacecraft (THB and THC, THD, THE) were situated on the magnetosheath side and magnetospheric side respectively. This provided a unique opportunity to directly observe the 3D geometry of an FTE across the MP. It is found that the axes of the magnetosheath section and magnetospheric arm of the FTE are approximately close to the directions of local magnetic field respectively, while the flux rope’s azimuthally extended section is found to lie approximately on the magnetopause surface and parallel to the X-line direction. (ii) The electron energy-pitch angle distribution in an FTE measured by Double Star-TC1 on 5 April 2004 show that its flux rope was composed of four types of magnetic field lines: (a) from the magnetosheath (MTH) → the northern magnetosphere (MSP) (open), from the southern MSP → MTH (open), from southern MSP → northern MSP (closed), and from MTH → MTH, indicating that the field lines must have reconnected multiple times. These two results help to improve our understanding of magnetic reconnection at the MP.
These works at Peking University was supported by the NSFC Grants 41274167, 40731056, 40974095, 41004072 and 10975012, the Chinese National Key Basic Research Science Foundation (2011CB811400), the Doctoral Fund of the Ministry of Education of China (20090001110012), and NASA (NNX10AL07G). The studies were initiated from a working group sponsored by ISSI, Berne, Switzerland. We acknowledge NASA contract NAS5-02099 for the use of data from the THEMIS Mission, C. W. Carlson and J. P. McFadden for use of ESA data, and K. H. Glassmeier, U. Auster and W. Baumjohann for use of FGM data, and C. Carr and H. Reme for providing the Double Star FGM and HIA data.
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Zhong, J., et al. (2013), Three-dimensional magnetic flux rope structure formed by multiple sequential X-line reconnection at the magnetopause, J. Geophys. Res. Space Physics, 118,1904–1911, doi:10.1002/jgra.50281.