X-ray imaging of a solar limb flare on 1982 January 22

Abstract

Simultaneous X-ray images in hard (20–40 keV) and softer (6.5–15 keV) energy ranges were obtained with the hard X-ray telescope aboard the Hinotori spacecraft of an impulsive solar X-ray burst associated with a flare near the solar west limb. The burst was composed of an impulsive component with a hard spectrum and a thermal component with a peak temperature of 2.8 × 107 K. For about one minute, the impulsive component was predominant even in the softer energy range. The hard X-ray image for the impulsive component is an extended single source elongated along the solar limb, rather steady and extends from the two-ribbon Hα flare up to 104 km above the limb. The centroid of this source image is located about 10″ (7 × 103 km) ± 5″ above the neutral line. The corresponding image observed at the softer X-rays is compact and located near the centroid of the hard X-ray image. The source for the thermal component observed in the later phase at the softer X-rays is a compact single source, and it shows a gradual rising motion towards the later phase.