The Magnetospheric Fluopause
Abstract
A global MHD simulation illustrates the relative contributions to magnetotail structure of two mantle models: the cusp-entry model in which the cusp is the proximal source of the mantle and the slow-mode expansion wave model in which the magnetosheath is the proximal source of the mantle. The simulation shows that both modes of plasma entry occur, and it reveals their relative contributions. The mantle, identified in the simulation as the volume of the tail occupied by a slow-mode expansion wave filled with magnetosheath plasma, lies mostly on streamlines that originate in the dayside cusp (cusp model), but the bulk of plasma inflow comes directly from the magnetosheath (magnetosheath model). The demarcation between streamlines originating in the cusp and streamlines originating in the magnetosheath is sharp. We call this demarcation the fluopause. The fluopause is the downwind extension of the solar wind stagnation streamline. At 100 Re downtail, the fluopause lies several Re inside the magnetopause identified by the peak in the electrical current that defines the magnetotail boundary. Whereas the magnetopause clearly marks the start of the slow-mode expansion wave that defines the mantle, all MHD parameters and their slopes are continuous across the fluopause. Streamlines on the magnetosheath side of the fluopause do not converge on the plasma sheet and, so, are not a likely source of particles for the plasma sheet. Streamlines on the cusp side of the fluopause do converge on the plasma sheet and, so, are likely candidates for the particles that supply the plasma sheet.
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2001
- Bibcode:
- 2001AGUSM..SM52D02S
- Keywords:
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- 2724 Magnetopause;
- cusp;
- and boundary layers;
- 2728 Magnetosheath;
- 2740 Magnetospheric configuration and dynamics;
- 2764 Plasma sheet