Physical parameter analysis of an intense, compact subflare

Abstract

Results of analysis of Skylab X-ray proportional counter data (10-s averages) and X-ray telescope filtergrams for the August 9, 1973 (SN/M2) subflare from McMath 12474 (NOAA AR 185) are presented. The event flux profiles and profiles of temperature, volume emission-measure, and a quantity equivalent to thermal energy content are shown. Using the proportional counter data, a peak temperature in excess of 20,000,000 K at 1552:05 UT, a peak volume emission measure of 7 x 10 to the 48th per cu cm at 1553:25 UT, and a peak value of thermal energy content of 2 x 10 to the 16th evgs/cm to the 3/2 power at 1552:45 UT were derived. Based on the analysis of spatially-resolved X-ray images during the period near flare-peak through flare-decay, the flare is observed to be both intense and compact and to consist of at least two identifiable loops whose volumes remained essentially unchanged throughout the event.