Spectral and temporal properties of narrowband dm-spikes and broadband pulses in the August 5, 2003 flare Original Research Article

On August 5, 2003 the Ondřejov radiospectrograph and the Brazilian Solar Spectrograph recorded simultaneously the narrowband dm-spikes superimposed on broadband pulses in the frequency ranges of 0.8–4.5 and 1.75–2.25 GHz, respectively. Using a new method of wavelet filtering broadband sub-second pulses with a frequency width of 0.48 GHz and narrowband millisecond spikes with a frequency width 0.13 GHz were recognized and analysed in detail. Filtered radio spectra showed that the spikes were clustered in stripes at different frequencies. These stripes drifted and their frequency ratios changed during short time intervals. Periods of the narrowband spikes and their stripes were ∼0.4 s and 4, 8–10, and 16 s, respectively. The main period of the broadband pulses was ∼4 s. Values of significant periods of the narrowband spikes coincided with those of the broadband pulses. We found significant peak-to-peak correlations with zero time lags among stripes of the narrowband spikes on different frequencies. The characteristics of the narrowband dm-spikes and broadband pulses indicate that mutually linked emission processes generate both fine structures.