Abstract

A detailed analysis of a limb flare on 2002 April 15 was carried out using RHESSI X-ray images and spectra, Nobeyama microwave images, Owens Valley Solar Array (OVSA) microwave spectra, and SOHO EIT & LASCO images. This M1.2 flare lasted about 40 minutes in GOES soft X-rays. RHESSI missed part of the decay phase of the flare. RHESSI images show a thermal flare loop at 6-25 keV and a bright thermal looptop source within the loop throughout the flare. At the peak of the flare, a coronal source 6 arcseconds above the flare loop and two clear-cut footpoints appear at 25-50 keV. Another coronal source above the loop at 10-25 keV ejected outward at about 600 km/s after the peak. By fitting the RHESSI spectra, we found that a low-energy cut-off at about 22 keV is required in order to get a consistent evolution of the thermal plasma parameters with time. After the hard X-ray peak, the flare loop moves outward in both the SOHO/EIT 195 Å band and the Nobeyama microwave images. It precedes an expanding coronal anomaly observed in SOHO/LASCO C2 images. We will show images and movies of our results, and a comparison of the microwave images and spectra with the RHESSI observations.

This project was supported in part by the RHESSI Project and the NASA Sun-Earth Connection Program.