Abstract:
Statistical analyses of the correlation events between the type Ⅲ radio bursts and Coronal Mass Ejections (CMEs) during 23rd cycle are presented, radio data were observed with the 20-420 MHz at the Radio Spectrograph Culgoora Solar Observatory in Australia. It is found that the relation between the decimetric type Ⅲ bursts and CMEs is not closer than the relation between the type Ⅱ radio bursts and CMEs. Most of metric type Ⅲ radio bursts occurred 25-30 min before CME, and about 72% CMEs events correlated with gradual flares. Meanwhile, the higher energy of theflare corresponds to the larger initial velocity of the correlated CMEs. As for impulsive flares, the type Ⅲ bursts are produced probably owing to the ejection of high energy electronic beam from the open magnetic line of force. And around the electronic beam and along the open magnetic line of force there simultaneously ejects a plasma block mass, which just form a small-scale CME. In this way, the type Ⅲ burst and CME occur in the same flare. As for gradual flare, a prominence is formed possibly owing to the uninterrupted upward floatation of the magnetic flux tube in the flare. The ejection matter of the prominence produces the large-scale CME, but on the edge of the magnetic flux loop there exists the open magnetic field line, the energetic electronic beam can eject and produce type Ⅲ bursts.