Kryshtal, A, Gerasimenko, S, Voitsekhovska, A et al. (1 more author) (2013) The ion-acoustic instability in the pre-flare plasma near the loop footpoints at solar active regions. Annales Geophysicae, 31 (12). 2193 - 2200. ISSN 0992-7689
Abstract
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. © Author(s) 2013.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2013 The Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
Keywords: | Solar physics, astrophysics, astronomy (photosphere and chromosphere) |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Automatic Control and Systems Engineering (Sheffield) The University of Sheffield > Faculty of Science (Sheffield) > School of Mathematics and Statistics (Sheffield) |
Funding Information: | Funder Grant number STFC ST/J001430/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 24 Jan 2014 09:54 |
Last Modified: | 16 Nov 2015 11:49 |
Published Version: | http://dx.doi.org/10.5194/angeo-31-2193-2013 |
Status: | Published |
Publisher: | Copernicus |
Refereed: | Yes |
Identification Number: | 10.5194/angeo-31-2193-2013 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:77608 |