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The Gyro-Synchrotron Radiation from Moving Type IV Sources in the Solar Corona
Published online by Cambridge University Press: 25 May 2016
Abstract
(Solar Phys.). Calculations of the gyro-synchrotron emission are made for conditions which might be expected in moving type IV sources in the solar corona. Two simple models for an evolving source are treated: a uniform cube and an inhomogeneous sphere. The results suggest that most moving sources have the following features: (1) A rather strong magnetic field, ≈ 10 G, is carried out within the source. This is required to achieve the high degree of circular polarization often observed. (2) Synchrotron self-absorption causes the source to be optically thick at frequencies less than about 100 MHz, thus restricting the bandwidth of the radiation. The self-absorption decreases as the source moves outward and expands. The turnover frequency, which separates the optically thick and thin spectral regimes, moves rapidly to lower frequencies, accompanied by a change from low to high circular polarization. In the case of an inhomogeneous source, the source appears to be larger at the lower frequencies. (3) Razin-Tsytovich suppression cannot be an important factor in determining the characteristics of most sources.
- Type
- Part IV Acceleration, Containement and Emission of High-Energy Flare Particles
- Information
- Symposium - International Astronomical Union , Volume 57: Coronal Disturbances , 1974 , pp. 481 - 482
- Copyright
- Copyright © Reidel 1974