Ballooning instability at the plasma sheet-lobe interface and its implications for polar arc formation

Physics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

3

Magnetospheric Physics: Mhd Waves And Instabilities (2149, 6050, 7836), Magnetospheric Physics: Magnetotail Boundary Layers, Magnetospheric Physics: Magnetosphere/Ionosphere Interactions (2431), Magnetospheric Physics: Auroral Phenomena (2407)

Scientific paper

Huang et al. (1987, 1989) reported hot filaments of plasma sheet origin filling the magnetospheric lobes during northward interplanetary magnetic field (IMF). On the other hand, cold plasma transients of presumably lobe origin are often observed in the plasma sheet. These features can be interpreted in terms of plasma exchange at the plasma sheet-lobe interface (PSLI) proceeding in a filamentary manner. We present a description of this process within ballooning destabilizing of the near-Earth curved segment of the PSLI. Although the basic ballooning instability condition is not typically met inside the plasma sheet, it is satisfied at this segment. The PSLI always separates the cold lobe population from the hot plasma sheet, thus providing a pressure gradient favorable for the instability; its near-Earth part has a nonnegligible magnetic curvature. A solution for the least stable ballooning harmonics is found, which satisfies the finite conductivity boundary condition in the ionosphere and the outgoing Alfvén wave condition at the tailward end of the near-Earth curved segment of the plasma sheet boundary. We show that this part of the PSLI may be a generator region launching filamentation. The background convection is imposed on the ballooning motions. The large-scale convection associated with southward IMF Bz suppresses hot filament progression into the lobes, while promoting penetration of lobe transients into the plasma sheet. However, during northward IMF, the convection favors at certain magnetic local times the extension of plasma sheet filaments into the lobes and their subsequent protrusion toward noon. This process is signified in the ionosphere by the occurrence of nightside originating polar arcs. Several polar arc events are shown that develop from the nightside oval boundary into the polar cap on timescales of approximately 10-15 min, consistent with the growth rates of the studied instability.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Ballooning instability at the plasma sheet-lobe interface and its implications for polar arc formation does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Ballooning instability at the plasma sheet-lobe interface and its implications for polar arc formation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ballooning instability at the plasma sheet-lobe interface and its implications for polar arc formation will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-1338963

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.