An observational study of the 2B/X2.8 flare of 30 March, 1982 in optical, radio, and X-ray ranges

Abstract

The 2B/X2.8 double-ribbon flare of 30 March, 1982 is investigated using Hα, white light, X-rays, and microwaves. The X-ray burst seems to consist of two components, i.e., an impulsive component showing a long chain of peaks and a thermal component (T ∼ 2 × 107 K). In the early phase, the source images for the impulsive component were available simultaneously at soft (7–14 keV) and hard (20–40 keV) X-rays. Both sources are elongated along a neutral line. The core of the source for the hard X-rays is located at one end which seems to be a footpoint (or a leg) of a loop or arcade, while the core for the soft X-rays is located at the center of the elongated source which would be the center of the loop. The core for the hard X-rays shifted to this center in the main and later phase, accompanied by decrease in the source size in the later phase. A peak of one-directional intensity distribution at 35 GHz always lies on the core of the hard X-ray source, showing a shift of the position synchronous with the hard X-ray core. This may imply a common source for the radio waves and the hard X-rays. The source of the thermal component observed at the soft X-rays (7–14 keV) after the early phase covers a whole Hα patches. This may imply a physical relation between the thermal X-ray loops and the Hα brightening.