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| Titel |
Observations of flux rope - associated particle bursts with GEOTAIL in the distant tail |
| VerfasserIn |
A. Belehaki, E. T. Sarris, G. Tsiropoula, R. W. McEntire, S. Kokubun, T. Yamamoto |
| 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 ; 15, no. 12 ; Nr. 15, no. 12, S.1515-1531 |
| Datensatznummer |
250013036
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| Publikation (Nr.) |
 copernicus.org/angeo-15-1515-1997.pdf |
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| Zusammenfassung |
Geotail energetic particle, magnetic field
data and plasma observations (EPIC, MGF and CPI experiments) have been examined
for a number of energetic particle bursts in the distant tail (120Re<|XGSM|<
130 Re), associated with moving magnetic field structures, following substorm
onsets. The features obtained from this data analysis are consistent with the
distant magnetotail dynamics determined first by ISEE3 observations and
explained in terms of the neutral line model. At the onset of the bursts, before
plasma sheet entrance, energetic electrons appear as a field-aligned beam
flowing in the tailward direction, followed by anisotropic ions. Within the flux
rope region, suprathermal ions exhibit a convective anisotropy, which allows
determination of the plasma flow velocity, assuming that the anisotropy arises
from the Compton-Getting effect. The velocities thus determined in the plasma
sheet are estimated to be 200–650 km/s, and compare favourably with the
velocities derived from the CPI electron and proton experiment. The estimated
length of magnetic field structures varies between 28 and 56 Re and depends on
the strength of the westward electrojet intensification. Finally, the three
structures reported here show clear magnetic field signatures of flux rope
topology. The existence of a strong magnetic field aligned approximately along
the Y-axis and centred on the north-to-south excursion of the field, and the
bipolar signature in both By and/or Bz components, is consistent
with the existence of closed field lines extending from Earth and wrapping
around the core of the flux rope structure.
Key words. Magnetospheric configuration and dynamics ·
Magnetotail |
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