 |
| Titel |
Extended period of polar cap auroral display: auroral dynamics and relation to the IMF and the ionospheric convection |
| VerfasserIn |
V. G. Vorobjev, S. V. Leontyev, Ya. I. Feldstein |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 13, no. 8 ; Nr. 13, no. 8, S.854-862 |
| Datensatznummer |
250011959
|
| Publikation (Nr.) |
 copernicus.org/angeo-13-854-1995.pdf |
|
|
|
|
|
| Zusammenfassung |
| An unusually extended period (5 h) of polar
cap auroral display on 3 August 1986 is examined. Auroras have been investigated
using ground-based data as well as measurements from the IMP-8 spacecraft in
interplanetary space and simultaneous observations from the polar-orbiting
satellites Viking and DE-1 in the northern and southern hemispheres,
respectively. It is found that visible Sun-aligned arcs are located inside the
transpolar band of the θ-aurora observed from the satellite in
ultraviolet wavelengths. The transpolar band can contain several Sun-aligned
arcs that move inside the band toward the morning or evening side of the auroral
oval independent of the direction of the band movement. Intensifications of
polar cap auroras with durations of up to about 30 min are observed. No change
has been found in either IMF parameters or substorm activity that can be related
to these intensifications. The θ-aurora occurred during a 2-h period
when the B z-component of the IMF was negative. A
tendency is noted for dawnward (duskward) displacement of the transpolar band
when By>0 (By<0) in the southern
hemisphere. Simultaneous observations of auroral ovals during interplanetary Bz<0,
By<0 and Bx>0 in both hemispheres and
convection patterns for Bz<0 and By<0
have been displayed using satellite and ground-based measurements. It was found
that the transpolar band of the <theta>-aurora in the sunlit hemisphere
was situated in the region of large-scale downward Birkeland currents. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|