 |
| Titel |
Strong sunward propagating flow bursts in the night sector during quiet solar wind conditions: SuperDARN and satellite observations |
| VerfasserIn |
C. Senior, J.-C. Cerisier, F. Rich, Mark Lester, G. K. Parks |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 20, no. 6 ; Nr. 20, no. 6, S.771-779 |
| Datensatznummer |
250014407
|
| Publikation (Nr.) |
 copernicus.org/angeo-20-771-2002.pdf |
|
|
|
|
|
| Zusammenfassung |
High-time resolution data
from the two Iceland SuperDARN HF radars show very strong nightside convection
activity during a prolonged period of low geomagnetic activity and northward
interplanetary magnetic field (IMF). Flows bursts with velocities ranging from
0.8 to 1.7 km/s are observed to propagate in the sunward direction with phase
velocities up to 1.5 km/s. These bursts occur over several hours of MLT in the
20:00–01:00 MLT sector, in the evening-side sunward convection. Data from a
simultaneous DMSP pass and POLAR UVI images show a very contracted polar cap
and extended regions of auroral particle precipitation from the magnetospheric
boundaries. A DMSP pass over the Iceland-West field-of-view while one of these
sporadic bursts of enhanced flow is observed, indicates that the flow bursts
appear within the plasma sheet and at its outward edge, which excludes Kelvin-Helmholtz
instabilities at the magnetopause boundary as the generation mechanism. In the
nightside region, the precipitation is more spot-like and the convection
organizes itself as clockwise U-shaped structures. We interpret these flow
bursts as the convective transport following plasma injection events from the
tail into the night-side ionosphere. We show that during this period, where the
IMF clock angle is around 70°, the dayside magnetosphere is not completely
closed.
Key words. Ionosphere (Auroral ionosphere; Ionospheremagnetosphere
interactions; Particle precipitation) |
| |
|
| Teil von |
|
|
|
|
|
|
|
|