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R.T. Scopes, J.T. Schmelz (University of Memphis)
Despite recent progress in understanding the solar corona, there are still important parameters and processes that remain elusive. Chief among them is the coronal heating problem, i.e., the precise physical mechanism(s) by which the solar atmosphere is heated to its million-degree temperatures. Although there is a rich database of theoretical models described in the literature, there are few diagnostic constraints that can help determine which of these possible models, if any, is correct. Insights into the nature of the heating mechanism can be gained through the analysis of differential emission measure curves localized along isolated coronal loops. Simultaneous observations of such a loop were taken on 20 April 98 with the SOHO-CDS and YOHKOH-SXT instruments. Plasma temperature distributions in the range log T = 4.5-7.5 at various positions along to loop were constructed using a forward-folding technique. This analysis used elemental abundance values from Fludra & Schmelz (1999, A & A, 348, 286) and ionization fractions from Arnaud & Raymond (1992, ApJ, 398, 394) for iron and from Arnaud & Rothenflug (1985, ApJS, 60, 425) for other elements. The differential emission measure curve at each pixel combined with knowledge of the loop geometry helped to pin down the coronal heating mechanism using the method described by Priest et al.(1998, Nature, 393, 545). This work is supported by NASA grant NAG5-7197.
The author(s) of this abstract have provided an email address for comments about the abstract: rscopes@aol.com