Solar radio continua and the X-ray emission during flares

Radio continua measured by the Ondrejov solar radio spectrograph in the frequency band 100-1000 MHz are compared with X-ray flux in the 2-320 keV region, measured with the Czechoslovak photometer aboard the Prognoz 8 satellite. 20 flare-associated events recorded by both instruments from March to August 1981 were chosen and, using the Solar Geophysical Data, source flares and their optical characteristics were determined. The following time coincidences between radio and X-ray phenomena were found in the analysis: 1. the low-frequency continuum (and pulsations) and the maximum of the soft X-ray flux; 2. the high-frequency continuum (and pulsations) and hard X-ray burst; 3. the group of type III bursts and hard X-ray burst; 4. hard X-ray burst and dm-spikes. The characteristics of these relationships are given and the physical consequences briefly discussed. (author). 1 tab., 3 figs., 8 refs