Dynamic Nature of Coronal Heating as Inferred from Simultaneous, Observations of the Quiet Sun at 20 cm Radio and He I 10830 Å
We present the results of the first simultaneous observations of the quiet Sun made at 20 cm (1.45 GHz) with the VLA and in He I 10830 Å, together with the line of sight component of the photospheric magnetic field. The correspondence between the emission at 20 cm, which originates from the low corona-transition region, and the He I chromospheric absorption reveals that only 40% of the radio sources, reminescent of coronal bright points, have strong He I ‘dark points’ associated with them. Temporal changes in the intensity of the emission at 20 cm and absorption in He I are often observed on a time scale of minutes. This dynamic behavior is also accompanied by changes in the spatial extent of the sources observed at 20 cm, and is more often associated with the cancellation than the emergence of magnetic flux. The nature of the correlation found between changes in He I dark points and the 20 cm radio sources, as well as with the underlying magnetic field, suggest that topological changes in the underlying magnetic field are playing an important role in the transient coronal heating process.
KeywordsRadio Emission Radio Source Coronal Heating Photospheric Magnetic Field Dark Point
Unable to display preview. Download preview PDF.
- Habbal, S. R. and Harvey, K. L. 1987, submitted to Astrophys. J. Google Scholar