The thermal phase of a large solar flare. [Skylab observations

EUV and X-ray observations are used to derive the differential emission measures, temperatures, densities, radiative and conductive cooling rates, and thermal energy content of a class 2B flare that occurred on September 7, 1973. The results of the analysis indicate that (1) most of the flare plasma was at temperatures between 3 and 10 million degrees; (2) the peak temperature decreased with time from about 8 million K to 5 million K over a period of 3.5 hours; (3) the differential emission measure steadily decreased with time at nearly all temperatures; (4) both radiation and conduction were important cooling mechanisms for the plasma at temperatures above 100,000 K; and (5) a substantial amount of energy, of the order of 3 x 10 to the 31st power ergs, was deposited in the flare loops after flare maximum. The empirically determined flare parameters are compared with similar parameters derived from a simple theoretical loop model.