THE MORPHOLOGY OF THE 10(7)-K PLASMA IN SOLAR-FLARES .1. NONIMPULSIVEFLARES

In this paper we have analyzed images of 48 C-, M-, and X-type flares which occurred between 1991 October and 1993 February. The images were recorded by the soft X-ray telescope (SXT) flown on the Japanese Yohk oh spacecraft. The spatial resolution of the recorded images is about 2.5''. In each of the recorded flares the brightest regions emitting t he 10(7) K radiation were analyzed and evaluated. The 10(7) K emitting region was found to be located at loop tops in the first well-exposed flare image recorded during the rise phase (within 1-2 minutes after flare onset), in images recorded near intensity peak, and in those rec orded during most of the decay phase. Occasionally, in the begining of the event when the total flare intensity is low, the brightness of th e footpoints may rival the brightness of the loop top. However, in the se cases it is expected that the temperature of the loop top is consid erably higher. The emitting region, even during flare peak, is very sm all (often smaller than a single SXT pixel 1800 x 1800 km).