Abstract
This study presents cross-sectional vector maps of the magnetic field derived from IMP 8 magnetometer in the magnetosheath at 30 Re behind the Earth. In addition the vector patterns of the magnetosheath field for northward, southward, and east-west interplanetary magnetic field (IMF) directions are qualitatively compared with those obtained from the Spreiter-Stahara gas dynamic (GD) and Fedder-Lyon magnetohydrodynamic models (MHD). The main purpose is to display the cross-sectional differences in relation to the dayside merging with different IMF directions, allowing the reader to make direct visual comparisons of the vector patterns. It is seen that for east-west IMF directions, the data-based and MHD-based patterns differ noticeably in a similar way from the GD model, presumably reflecting the influence of dayside magnetic merging of the Earth's magnetic field with the y-component of the interplanetary magnetic field. All three northward IMF cross sections show comparable field draping patterns as expected for a closed magnetosphere. For southward IMF case, on the other hand, differences between the three cross-sectional patterns are greater as seen in the field vector sizes and directions, especially closer to the magnetopause where more disturbed magnetospheric conditions are known to be exist. The data comparisons with the MHD and GD models show that the differences result from the magnetic field-flow coupling and that the effects of dayside reconnection are present in IMP 8 magnetic field measurements.
Original language | English |
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Pages (from-to) | 376-387 |
Number of pages | 12 |
Journal | Annales Geophysicae |
Volume | 16 |
Issue number | 4 |
DOIs | |
Publication status | Published - Apr 1998 |
Funding
Acknowledgements. This work was supported by NSF (grant ATM 91-17484, University of California, Los Angeles). The author would like to thank J. Fedder, J. Lyon and S. Slinker for discussions about the MHD code and providing the MHD model data; to J. Spreiter and S. Stahara for providing the gas dynamic model code; and to G.L. Siscoe and J.G. Luhmann for useful conversations on the several aspects of this work.
Funders | Funder number |
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National Science Foundation | ATM 91-17484 |
University of California |
Keywords
- IMP 8 magnetometer
- Interplanetary magnetic fields
- Vector maps