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| Titel |
Energy time dispersion of a new class of magnetospheric ion events observed near the Earth's bow shock |
| VerfasserIn |
G. C. Anagnostopoulos, N. Paschalidis, A. N. Littas |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 18, no. 1 ; Nr. 18, no. 1, S.28-41 |
| Datensatznummer |
250013878
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| Publikation (Nr.) |
 copernicus.org/angeo-18-28-2000.pdf |
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| Zusammenfassung |
We have analyzed high time resolution (\geq6
s) data during the onset and the decay phase of several energetic (\geq35 keV)
ion events observed near the Earth's bow shock by the CCE/AMPTE and IMP-7/8
spacecraft, during times of intense substorm/geomagnetic activity. We found that
forward energy dispersion at the onset of events (earlier increase of middle
energy ions) and/or a delayed fall of the middle energy ion fluxes at the end of
events are often evident in high time resolution data. The energy spectra at the
onset and the decay of this kind of events show a characteristic hump at middle
(50-120 keV) energies and the angular distributions display either anisotropic
or broad forms. The time scale of energy dispersion in the ion events examined
was found to range from several seconds to \sim1 h depending on the ion energies
compared and on the rate of variation of the Interplanetary Magnetic Field (IMF)
direction. Several canditate processes are discussed to explain the observations
and it is suggested that a rigidity dependent transport process of
magnetospheric particles within the magnetosheath is most probably responsible
for the detection of this new type of near bow shock magnetospheric ion events.
The new class of ion events was observed within both the magnetosheath and the
upstream region.
Key words. Interplanetary physics (energetic particles;
planetary bow shocks) |
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