Development of coronal mass ejections: Radio shock signatures

We present observational imaging evidence for the existence of metric radio bursts closely associated with the front edge of coronal mass ejections (C MEs). These radio bursts drift in frequency similarly to type II bursts. Th ey are weak and usually go undetected on spectrograph data. We find the sam e measured projected velocity for the displacement of, respectively, the ra dio source (when observed at two or more frequencies) and the CME leading e dge. The position of the emitting source coincides with the CME leading edg e. Among the events analyzed, the fastest of them, with a velocity over 140 0 km s(-1), was associated with interplanetary type II bursts.