Detection of large-scale radio structure and plasma flow during a solar bright point flare

We report on the detection of a large-scale radio structure and plasma flow associated with a bright point flare observed on 1993 July 11. The bright point (BP) flare was simultaneously imaged by the Nobeyama radioheliograph at 17 GHz and the Soft X-Ray Telescope on board the Yohkoh mission. The microwave emission consists of a large-scale structure and a compact moving source. The large-scale component seems to be the radio counterpart of large-scale loop structures sometimes observed in association with BP flares in X-rays. The compact source moved from the location of the X-ray BP flare with a speed of about 60 km s(-1), which suggests a plasma flow. Spatial comparison between X-ray and radio data shows that the BP flare had different manifestations in the two wavelength domains. The emission peaks in the two wavelength domains did not coincide, which suggests cool plasma flow along the large-scale radio structure. We were able to determine the temperature and emission measure of the BP flare plasma from the X-ray data, and thus we computed the expected radio flux from the X-ray-emitting plasma. We found that the computed radio flux was much smaller than the total observed radio flux.