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

✍ Scribed by K. F. Tapping


Publisher
Springer
Year
1978
Tongue
English
Weight
578 KB
Volume
59
Category
Article
ISSN
0038-0938

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✦ Synopsis


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.

2. The Observations

The observations were made using the 10 m diameter, fully steerable paraboloid at Cranleigh (U.K.). The receiver operated on a frequency of 140 MHz, had a predetection bandwidth of 1 MHz and a post-detection bandwidth including the chart recorder, of more than 50 Hz. The overall system noise temperature was better than 200 K.

In order to confirm the solar origin of the observed events, aural monitoring was carried out during the observing period and at intervals, the antenna was directed off-source.