Nobeyama Radio Observatory, Minamimaki, Minamisaku, Nagano 384-1305, Japan

Flare-associated bursts in the decimetric range are probably the most complex and least understood of all (Dulk, McLean & Wilson 1985). However, recent studies combining high resolution spectral and imaging observations make it possible to clear the formation of these emissions (e.g., Aurass 1999). We have analyzed flare radio decimetric signatures containing a group of fast-drifting substructures lasting longer than 30s. Although most of these events show a flat envelope of the decimetric spikes, we found three events that clearly show a negative slope in the envelope associated with a plasma cloud ejection (Hori 1999). On the basis of a detailed comparison between the radio dynamic spectra and spatially-resolved multi-wavelengths observations, we discuss where and when the decimetric bursts are emitted.

REFERENCES

Aurass, H., Proceedings of Nobeyama Symposium on Solar Physics with Radio Observations, 1999, in press

Dulk, G. A., McLean, D. J., and Nelson, G. J., 1985, Solar Radiophysics, eds. D. J. McLean and N. R. Labrum, (Cambridge: Cambridge Univ. Press.), 54.

Hori, K., Proceedings of Nobeyama Symposium on Solar Physics with Radio Observations, 1999, in press