Compact, Variable, Moving Sources on the Sun at 2 CM Wavelength,
Abstract
The high angular resolution provided by the Very Large Array (VLA) has permitted the spatial resolution of solar microwave sources and opened the way for comparisons with observations of similar angular resolution at optical and X ray wavelengths. High resolution VAL observations of solar active regions at relatively long wavelengths of 6 cm and 20 cm have, for example, led to the discovery of the microwave counterpart of the ubiquitous coronal loops that had previously only been observed by X ray telescope lofted above the Earth's atmosphere. The microwave emission of the coronal loops is attributed to the gyroresonant radiation and /or the bremsstrahlung of million-degree thermal electrons trapped within the loops by strong magnetic fields; observations of this emission have provided valuable new insights into the nature of solar active regions and eruptions from the Sun and nearby stars. In contrast, the short wavelength 2 cm emission of solar active regions is poorly understood. In spite of numerous VLA solar observations at 2 cm, there are only two published results. In both instances, compact (angular sizes about 15 sec.), highly polarized (degree of circular polarization 80% to 90%) sources were found in regions of strong magnetic field (strength H about 2,000 G) above sunspots.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1986
- Accession Number
- ADA173279
Entities
People
- Kenneth R. Lang
- Robert F. Willson
Organizations
- Tufts University