Microwave and soft X-ray emission from a flare-activated coronal loop

We study the microwave and soft X-ray emissions produced by a flare-activated coronal loop, using total power spectral data from the Owens Valley Radio Observatory Solar Array, as well as soft X-ray data from the Yohkoh Soft X-ray Telescope, and the GOES soft X-ray monitors. We show that both the microwave and soft X-ray emissions, late in the loop development, can be well understood as thermal bremsstrahlung (free-free emission) from a hot (∼8 MK) plasma. From an investigation of the microwave spectrum we suggest that an overlying or cospatial, cooler (∼4 MK) plasma may also be present. We also study the time development of the loop, as observed with the three instruments. The loop appears to grow in size from a lower lying, initially invisible loop. New loops appear at greater heights, or else the initial loop rises at a top speed of more than 150 km s^-1, but the growth of the loop or loops slows after about 3 minutes and becomes stable at its inflated size. We study the subsequent brightening of the loop, using the SXT, GOES, and microwave data to investigate the changing physical parameters of the loop as it evolves.