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| Titel |
Observations of substorm fine structure |
| VerfasserIn |
L. L. Lazutin, R. Rasinkangas, T. V. Kozelova, A. Korth, H. Singer, G. Reeves, W. Riedler, K. Torkar, B. B. Gvozdevsky |
| 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 ; 16, no. 7 ; Nr. 16, no. 7, S.775-786 |
| Datensatznummer |
250013338
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| Publikation (Nr.) |
 copernicus.org/angeo-16-775-1998.pdf |
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| Zusammenfassung |
Particle and magnetic field measurements on
the CRRES satellite were used, together with geosynchronous satellites and
ground-based observations, to investigate the fine structure of a magnetospheric
substorm on February 9, 1991. Using the variations in the electron fluxes, the
substorm activity was divided into several intensifications lasting about 3–15
minutes each. The two main features of the data were: (1) the intensifications
showed internal fine structure in the time scale of about 2 minutes or less. We
call these shorter periods activations. Energetic electrons and protons at the
closest geosynchronous spacecraft (1990 095) were found to have comparable
activation structure. (2) The energetic (>69 keV) proton injections were
delayed with respect to electron injections, and actually coincided in time with
the end of the intensifications and partial returns to locally more stretched
field line configuration. We propose that the energetic protons could be able to
control the dynamics of the system locally be quenching the ongoing
intensification and possibly preparing the final large-scale poleward movement
of the activity. It was also shown that these protons originated from the same
intensification as the preceeding electrons. Therefore, the substorm instability
responsible for the intensifications could introduce a negative feedback loop
into the system, creating the observed fine structure with the intensification
time scales.
Key words. Magnetospheric Physics (Storms and
substorms). |
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