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
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.