 |
| Titel |
On the supply of heavy planetary material to the magnetotail of Mercury |
| VerfasserIn |
D. C. Delcourt |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 31, no. 10 ; Nr. 31, no. 10 (2013-10-08), S.1673-1679 |
| Datensatznummer |
250086119
|
| Publikation (Nr.) |
 copernicus.org/angeo-31-1673-2013.pdf |
|
|
|
|
|
| Zusammenfassung |
| We examine the transport of low-energy heavy ions of planetary origin
(O+, Na+, Ca+) in the magnetosphere of Mercury. We show that,
in contrast to Earth, these ions are abruptly energized after ejection into
the magnetosphere due to enhanced curvature-related parallel acceleration.
Regardless of their mass-to-charge ratio, the parallel speed of these ions is
rapidly raised up to ~ 2 VE × B (denoting by VE × B
the magnitude of the local E × B drift speed), in a like
manner to Fermi-type acceleration by a moving magnetic mirror. This parallel
energization is such that ions with very low initial energies (a few tenths
of eVs) can overcome gravity and, regardless of species or convection rate,
are transported over comparable distances into the nightside magnetosphere.
The region of space where these ions reach the magnetotail is found to extend
over altitudes similar to those where enhanced densities are noticeable in
the MESSENGER data, viz., from ~ 1000 km up to ~ 6000 km in
the pre-midnight sector. The observed density enhancements may thus follow
from E × B related focusing of planetary material of
dayside origin into the magnetotail. Due to the planetary magnetic field
offset, an asymmetry is found between drift paths anchored in the Northern
and Southern hemispheres, which puts forward a predominant role of heavy
material originating in the Northern Hemisphere in populating the innermost
region of Mercury's magnetotail. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|