Study of coronal loops from GOES/­SXI images

LÓPEZ FUENTES, M.C.; MANDRINI, C.H.; KLIMCHUK, J.A.

Annapolis

Workshop; Workshop; Solar Image Processing Workshop II; 2004

NASA - ESA

We study the evolution of coronal loops observed byGOES-SXI. Although this instrument has a coarser spatial resolution than TRACE or SXT, it has the advantage of continuous temporalcoverage. Then, we are able to obtain light curves of loopsfor longer periods than in previous works based on SXT observations(see e.g., Porter and Klimchuk 1995, ApJ, 454, 499).Applying the filter ratio technique using images observed in different instrument passbands we infer the temperature and emission measureof observed loops. We compute the timescales of the radiative and conductive cooling and we find that they are typically 1 order of magnitude shorter than the evolutionary timescales. We show that this situation can be alternatively explained by steady heating or impulsive heating by nanoflares. We compare the studiedSXI loops with loops observed by TRACE and SXT and we discuss theimplications in terms of both possible heating scenarios.