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| Titel |
The ion-acoustic instability in the pre-flare plasma near the loop footpoints at solar active regions |
| VerfasserIn |
A. Kryshtal, S. Gerasimenko, A. Voitsekhovska, V. Fedun |
| 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 ; 31, no. 12 ; Nr. 31, no. 12 (2013-12-16), S.2193-2200 |
| Datensatznummer |
250086161
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| Publikation (Nr.) |
 copernicus.org/angeo-31-2193-2013.pdf |
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| Zusammenfassung |
| The necessary physical conditions for development of the ion-acoustic
instability in the chromospheric part of a flaring loop current circuit are
investigated. Two possible scenarios have been studied. First, we consider
that pre-flare loop plasma with the large-scale sub-Dreicer electric field
has a classical Coulomb conductivity and, second, when anomalous resistance
appears due to saturation of Bernstein turbulence. The Fontenla-Avrett-Loeser (FAL) model of the solar
atmosphere was used to describe the pre-flare plasma. We have shown that
investigated instability can grow and develop either in the presence of the
Coulomb conductivity or saturated Bernstein turbulence. We demonstrate that
in the case of small-scale instability, the threshold value for the degree of
nonisothermality is high and, therefore, cannot be reached by inclusion of
the ordinary Joule heating. The ion-acoustic instability can develop at the
pre-flare loop footpoints provided the electrons are more than 10 times
hotter than the ions there. |
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