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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Asymmetric precipitation in a coronal loop as explanation of a singular observed spectrum

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Author(s):
Cristiani, G. [1] ; Gimenez de Castro, C. G. [2] ; Mandrini, C. H. [1] ; Machado, M. E. [3] ; Rovira, M. G. [1]
Total Authors: 5
Affiliation:
[1] Univ Buenos Aires, Inst Astron & Fis Espacio, RA-1428 Buenos Aires, DF - Argentina
[2] Escola Engn, Ctr Radio Astron & Astrofis Mackenzie, BR-01302907 Sao Paulo - Brazil
[3] Comis Nacl Actividades Espaciales, RA-1063 Buenos Aires, DF - Argentina
Total Affiliations: 3
Document type: Journal article
Source: Advances in Space Research; v. 44, n. 11, p. 1314-1320, DEC 1 2009.
Web of Science Citations: 2
Abstract

Almost 10 years of solar submillimeter observations have shown new aspects of solar activity, such as the presence of rapid solar spikes associated with the launch of coronal mass ejections and an increasing submillimeter spectral component in flares. We analyse the singular microwave-submillimeter spectrum of an M class solar flare on 20 December, 2002. Flux density observations measured by Sun patrol telescopes and the Solar Submillimeter Telescope are used to build the radio spectrum, which is fitted using Ramaty's code. At submillimeter frequencies the spectrum shows a component different from the microwave classical burst. The fitting is achieved proposing two homogeneous sources of emission. This theoretical fitting is in agreement with differential precipitation through a magnetically asymmetric loop or set of loops. From a coronal magnetic field model we infer an asymmetric magnetic structure at the flare location. The model proposed to quantify the differential precipitation rates due to the asymmetry results in a total precipitation ratio Q(2)/Q(1) approximate to 10(4)-10(5), where Q(1)(Q(2)) represents the total precipitation in the loop foot with the high (low) magnetic field intensity. This ratio agrees with the electron total number ratio of the two sources proposed to fit the radio spectrum. (C) 2009 COSPAR. Published by Elsevier Ltd. All rights reserved. (AU)

FAPESP's process: 99/06126-7 - Applications for the sub-milimeter Solar Telescope (SST)
Grantee:Pierre Kaufmann
Support type: Research Projects - Thematic Grants