RELATIONSHIP BETWEEN COLD AND HOT POST-SOLAR FLARE LOOPS AND THE IMPACT ON THE RECONNECTION FLARE MODEL

Citation
U. Feldman et Jf. Seely, RELATIONSHIP BETWEEN COLD AND HOT POST-SOLAR FLARE LOOPS AND THE IMPACT ON THE RECONNECTION FLARE MODEL, The Astrophysical journal, 450(2), 1995, pp. 902-906
Citations number
22
Categorie Soggetti
Astronomy & Astrophysics
Journal title
ISSN journal
0004637X
Volume
450
Issue
2
Year of publication
1995
Part
1
Pages
902 - 906
Database
ISI
SICI code
0004-637X(1995)450:2<902:RBCAHP>2.0.ZU;2-5
Abstract
The relationship between cold and hot postflare loops has been studied using the 1973 September 7 and 1974 January 15 flare images recorded by the Skylab S082 spectroheliograph. The images are of intense emissi on lines in the extreme ultraviolet region that span the 1 x 10(4) (He I) to 3.2 x 10(6) K (Ni XVIII) temperature range. The analysis of the images does not support the widely held notion that cold loops are al ways smaller than hot loops, lie below hot loops, and are similar in s hape. It is found that the coldest and hottest loops often differ sign ificantly in size and shape. Based on the analysis of a time sequence of Skylab images of cold and hot loops, there is no evidence that the loop system expands in a discontinuous manner, as would be the case if higher loops were sequentially formed and activated by reconnection o f the magnetic field. It is found that the individual coronal loops ex pand in a gradual manner. These conclusions are consistent with images of postflare loop systems in the 10(7) K range that were recorded by the soft X-ray telescope on the Yohkoh spacecraft. Previous observatio ns and interpretations of postflare loop systems, which led to the for mulation of the reconnection flare model are reexamined. In light of r ecent high-quality imagery that spans the temperature range from 10(4) to 10(7) K, it is concluded that the observations do not support all aspects of the reconnection flare model as presently articulated. Elem ents of the reconnection hare model that are inconsistent with the mod ern observations should be reconsidered.