The radiation, resulting from the nonlinear interaction of whistler solitons, which act as localized antennae, with the upperhybrid waves in the coronal loop, is shown to give rise to fine structures in solar radio bursts. All the observed features of microwave spikes in radio flares,e.g. their frequency, polarization and short duration can be explained by the presence of about 106 solitons occupying a volume of ∼ 108 m3, provided this interaction takes place at low altitudes. However, if this interaction takes place close to the top of the coronal loop, it gives rise to the isolated tadpole ‘eyes’ features in the dynamic spectra. About 109 solitons are needed to account for the observed flux of these ‘eyes’.
Volume 93 | Issue 5
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