Predictions of Merging of Interplanetary Magnetic Field Lines in the Magnetosheath
Abstract
The Integrated Space Weather Prediction Model (ISM) has been used to investigate how a tangential discontinuity in the interplanetary magnetic field (IMF) propagates through the magnetosheath to interact with the magnetosphere. A reversal in IMF Y or Z components at the inflow boundary of the simulation domain (at X = 40 RE) forms a tangential discontinuity that propagates through the bow shock and magnetosheath to interact with the magnetopause. The discontinuity becomes distorted as it is slowed in the magnetosheath and currents are locally enhanced. Signatures of merging between IMF field lines on either side of the discontinuity are seen in magnetic field line traces and in velocities. When merging occurs, these signature features are well separated from merging occurring at the magnetopause. Surprisingly, the increase in magnetosheath velocity in the Z direction in the exit cones of the merging region is larger for south-to-north turnings than in north-to-south turnings in the simulation. This evidently reflects that magnetic merging at the magnetopause changes magnetosheath conditions well away from the magnetopause. As a result of magnetosheath merging, a segment of the IMF is inhibited from contact with the magnetopause as it propagates downstream. Implications of these simulation results with respect to observations will be discussed.
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2001
- Bibcode:
- 2001AGUSM..SM52E01M
- Keywords:
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- 2728 Magnetosheath;
- 2740 Magnetospheric configuration and dynamics;
- 2784 Solar wind/magnetosphere interactions