 |
| Titel |
The size of the auroral belt during magnetic storms |
| VerfasserIn |
N. Yokoyama, Y. Kamide, H. Miyaoka |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 16, no. 5 ; Nr. 16, no. 5, S.566-573 |
| Datensatznummer |
250013276
|
| Publikation (Nr.) |
 copernicus.org/angeo-16-566-1998.pdf |
|
|
|
|
|
| Zusammenfassung |
Using the auroral boundary index derived from
DMSP electron precipitation data and the Dst index, changes in the size
of the auroral belt during magnetic storms are studied. It is found that the
equatorward boundary of the belt at midnight expands equatorward, reaching its
lowest latitude about one hour before Dst peaks. This time lag depends
very little on storm intensity. It is also shown that during magnetic storms,
the energy of the ring current quantified with Dst increases in
proportion to Le–3, where Le is
the L-value corresponding to the equatorward boundary of the auroral belt
designated by the auroral boundary index. This means that the ring current
energy is proportional to the ion energy obtained from the earthward shift of
the plasma sheet under the conservation of the first adiabatic invariant. The
ring current energy is also proportional to Emag, the total
magnetic field energy contained in the spherical shell bounded by Le
and Leq, where Leq corresponds to the
quiet-time location of the auroral precipitation boundary. The ratio of the ring
current energy ER to the dipole energy Emag
is typically 10%. The ring current leads to magnetosphere inflation as a result
of an increase in the equivalent dipole moment.
Key words. Ionosphere (Auroral ionosphere) ·
Magnetospheric physics (Auroral phenomena; storms and substorms) |
| |
|
| Teil von |
|
|
|
|
|
|
|
|