Abstract

Nobeyama Radioheliograph operates at 17 GHz and realizes high spatial and time resolution imaging capabilities of the whole Sun with high image quality. The objective of this instrument is to study various phenomena in the solar atmosphere, putting stress on active phenomena such as flares and active region evolution. From initial observations of solar flares, the following topics are presented: a thermal flare suggesting plasma heating through loop-loop interaction; prominence eruption followed by formation of arcade loops as evidence of energy release through magnetic reconnection; impulsive flares interpreted as production of nonthermal electron beams; and an intense flare initiated by preflare activities.