FINE-STRUCTURE IN A METRIC TYPE-IV BURST - MULTISITE SPECTROGRAPHIC, POLARIMETRIC, AND HELIOGRAPHIC OBSERVATIONS

The spectral fine structure of solar radio continua is thought to reve al wave-particle and wave-wave interactions in magnetic traps in the s olar corona. We present observations of spectra, polarization, and spa tial characteristics of combined emission/extinction features ('zebra patterns') during a decimetric/metric type IV event on 5 June, 1990. V ery high modulation depths are observed. The size and location of the sources during emission and extinction are determined for the first ti me. Two remarkable features are found: (1) The sources of emission str ipes have finite size, up to nearly 2'; during extinction stripes the brightness is reduced across the whole extent of the unperturbed conti nuum, which is slightly larger than 2'. (2) During emission stripes th e sources drift over distances up to several x 10(4) km, with apparent velocities up to 10(5) km s(-1). The observed features are briefly di scussed with respect to interpretations based on wave-particle interac tions and on the scattering of electromagnetic waves.