Thermal cyclotron radiation from solar active regions
Abstract
Fine structure resulting from thermal cyclotron emission in the microwave spectra of solar active regions is examined. Following a review of the cyclotron emission mechanism in the inhomogeneous magnetic fields above sunspots and the generation conditions for the typical S-component radiation, consideration is given to the thermal cyclotron radiation spectra expected for the cases of magnetic fields with maxima below and above the lower edge of the corona, a thin force tube of a bipolar magnetic field filled by hot electrons above a sunspot, and a neutral current sheet. It is thus shown that magnetic field and electron density distributions within the solar atmosphere can be determined from observation of the fine structure of the cyclotron lines and high-frequency cut-offs and the microwave polarization. Such observations would require the use of swept-frequency or multichannel receivers in combination with highly directional antennas.
- Publication:
-
Radio Physics of the Sun
- Pub Date:
- 1980
- DOI:
- 10.1017/S0074180900036676
- Bibcode:
- 1980IAUS...86...87Z
- Keywords:
-
- Cyclotron Radiation;
- Solar Activity Effects;
- Solar Radiation;
- Solar Radio Emission;
- Thermal Radiation;
- Brightness Temperature;
- Microwave Emission;
- Neutral Sheets;
- Solar Corona;
- Solar Magnetic Field;
- Solar Physics