Astronomy and Astrophysics – Astrophysics
Scientific paper
Dec 2007
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007agufmsm13a1115s&link_type=abstract
American Geophysical Union, Fall Meeting 2007, abstract #SM13A-1115
Astronomy and Astrophysics
Astrophysics
2740 Magnetospheric Configuration And Dynamics, 2760 Plasma Convection (2463), 2764 Plasma Sheet, 2790 Substorms
Scientific paper
This investigation uses plasma and magnetic field observations taken onboard the Geotail satellite near perigee (-9 RE > XGSE > -12 RE) in the midnight sector of the plasma sheet during geomagnetic bays (driven activity) and near times of substorm onsets and pseudobreakups (unloading activity). Injections are comprised of low-entropy flux tubes ("bubbles") that have lower pV5/3 than their pre-onset predecessors. Interchange with their surroundings result in their injection earthward. Injected flux tubes have pV5/3 ≤ 0.08 nPa(RE/nT)5/3, a value observed at geosynchronous altitude during injections. In pseudobreakups, observed pV5/3 returns to its larger, pre-onset values within a few minutes, whereas for substorm expansions, pV5/3 remains at depressed levels through the expansion phase. Geomagnetic bays are episodes of driven activity evidenced by enhanced eastward and westward electrojets, enhanced convection and a stable auroral band across the nightside. Steady magnetospheric convection (SMC) intervals are geomagnetic bays that do not show unloading activity. During geomagnetic bays, pV5/3 < 0.08 nPa(RE/nT)5/3 in the near-Earth plasma sheet, typical of low-entropy, expansion-phase flux tubes rather than high-content, growth-phase flux tubes. While we cannot say how such low-entropy flux tubes were formed during geomagnetic bays and SMCs, their presence allows Earthward convection to proceed into the inner plasma sheet without encountering the pressure-balance catastrophe.
Erickson Gary M.
Savoie A. M.
No associations
LandOfFree
The Role of Low-Entropy Flux Tubes During Geomagnetic Activity 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 The Role of Low-Entropy Flux Tubes During Geomagnetic Activity, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Role of Low-Entropy Flux Tubes During Geomagnetic Activity will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1421030