Thermodynamic history of a solar active region observed in X-rays

Abstract

The structure and energy content of an active coronal volume during its early history are investigated using soft X-ray images secured with the glancing-incidence telescope on Skylab. During the late stages of emerging-flux-region activity, the maximum temperatures exceeded 6.5 million K. At that time, the temporal rate of change in thermal energy content was about 10 to the 25th power ergs/s and was comparable to the rate of energy loss by radiation. Fluctuations in the energy content of the X-ray source region imply that this coronal active region was probably not in energy equilibrium during the five days of observation.