Meter wavelength pulsating bursts during the May 21, 1972, solar noise storm

During the May 21, 1972, noise storm, flux density measurements were made, at a frequency of 140 MHz, of 14 pulsating bursts. These comprised trains of up to 20 pulses, having pulse repetition rates of up to 15 s^–1.A model for the burst mechanism is described, based upon the hypothesis that the pulsations are generated by the modulation of a thermally damped plasma wave source by periodic trains of whistler packets originating in unstable regions deep in the corona and passing through the meter wavelength source. These whistler packets further enhance the emissions by increasing the efficiency of the conversion of the plasma waves into electromagnetic waves.