Electrodynamic Processes in Solar Magnetic Loops and their Relation to the Low-Frequency Modulations of Solar Microwave Emissions
Abstract
The spectral and temporal evolutions of the low-frequency (LF) pulsations modulating the solar microwave radiation (37 GHz) recorded at the Metsähovi Radio Observatory were studied by means of the data analysis algorithm based on a fast Fourier transformation with a sliding window. Attention is paid to the fact that the intensity of microwave radiation of solar flares, produced by the electron gyrosynchrotron mechanism, is dependent on a value of the background magnetic field (Dulk, 1985). Thus, slow variations of the magnetic field associated with disturbances of the electric current in a radiating source, should modulate the intensity of the microwave radiation. The dynamic spectra of the LF pulsations, quite often contain several spectral tracks, which can be interpreted as an indication that the radiation is produced in a system consisting of several closely located magnetic loops involved in a common global dynamical process. Application of the equivalent electric circuit models of the loops with inclusion of the effects of electromagnetic inductive interaction in groups of slowly growing current-carrying magnetic loops allows to explain and reproduce the main dynamical features of the observed LF modulation dynamic spectra. Detailed derivation of the equivalent electric circuit equation for a coronal magnetic loop is provided.
- Publication:
-
Central European Astrophysical Bulletin
- Pub Date:
- 2006
- Bibcode:
- 2006CEAB...30...97K
- Keywords:
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- solar flares;
- magnetic loops;
- oscillations;
- microwave radiation