Short-period pulsations in solar hard X-ray bursts recorded by Venera 13, 14

Solar flare information acquired by the Venera 13 and Venera 14 space probes has been analyzed and the results are reported. Power spectrum analyses of the 140 burst events were compared using the maximum entropy method, and the analytical results for several events are given along with data based on H-alpha observations. Each of these events is briefly described. The analysis demonstrates that the X-ray flux varies quasi-periodically with a period of roughly 1 sec in about three percent of the flares monitored. These fluctuations result from activity in individual magnetic field regions in which conditions inducing a periodic modulation of the hard X-ray flux may persist for an appreciable length of time.