Investigation of the energy release in long-duration flares

We investigate an example of long-duration arcade flare of 14/15 May 1993. Its spatial structure can be reliably determined from the Yohkoh X-ray images and Kitt Peak magnetograms. Temperatures, densities and heights of the loop-top flare kernels have been estimated from these data and also the kernel heating has been investigated in detail. We have found that (1) The energy release in the loop-top flare kernels occurs also during the whole flare decay phase; (2) The kernel evolution during the decay phase is quasi-steady-state, i.e. it is determined by the slow decrease of the heating rate, E-H(t). (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.