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On the Interpretation of Solar Radio-Burst Positions in a Scattering Corona

Published online by Cambridge University Press:  25 April 2016

A. C. Riddle
A. C. Riddle*
Affiliation:
Division of Radiophysics, CSIRO, Sydney
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Extract

Current observations and theories of solar bursts of types I, II and III suggest that the observed radiation may be emitted at a frequency close to the (fundamental) plasma frequency or its second harmonic. Refraction in a spherically symmetric corona would prevent radiation at the plasma frequency from reaching the observer except when the source is near the centre of the solar disk. However, it is found that fundamental frequency bursts are observed from anywhere on the disk. Recent analyses by Steinberg et al. and Riddle, in which the scattering of the radiation by coronal inhomogeneities was considered (in addition to refraction in an otherwise spherically symmetric corona), show that the radiation can escape from the plasma level and be observed for sources positioned almost anywhere on the disk. In addition, these authors and Fokker showed that a point source of radiation at the plasma frequency, or its harmonic, would be observed as an extended source with dimensions comparable with those observed. One implication was that the true source size is much smaller than the observed size.

Type
Contributions
Information
Publications of the Astronomical Society of Australia , Volume 2 , Issue 3 , October 1972 , pp. 148 - 150
Copyright
Copyright © Astronomical Society of Australia 1972

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References

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