Special observation of solar active area and forecasting and alarm system

The outline of the problems of solar flare is described in relation with its forecasting. In this paper, ''flare'' means a series of burst including electromagnetic radiation and particle emission. The flare is divided into leading stage, burst stage and second acceleration stage. The leading stage is the stage in which bright spot appears in Hα image along the neutral line of magnetic field in the direction of line of vision, and radio wave increases sometimes as precursor. In the burst stage, accompanying the two-ribbon type flare of Hα, X-ray and radio wave bursts are observed. At the second acceleration stage, further acceleration to higher energy region is carried out on the stage of corona. Two viewpoints are considered on the forecasting of flare. One is the forecasting of the small size flare which is not accompanied by the second acceleration stage, and the other is that of larger one which is called proton flare. The number of the small flare is large and the forecasting may be possible. Studies on the proton flare are in progress with the use of optical instruments and by radio wave method. (Kato, T.)