Skylab observations of the coronal structure overlying a type III producing active region

The coronal structure overlying, and presumably associated with, an isolated active region, McMath 12686, is identified during its west limb passage 15–17 January 1974. The region had a flaring site on its border close to a plage filament and exhibited various forms of activity, including type III burst production, during the three days of study. Although the coronal structure overlying the region was of small scale, its estimated electron density was 10 × that of the background corona, and it varied in density by a factor of two over a time scale of hours. Some implications of such a structure on the interpretation of type III emission are considered.On leave from Meudon Observatory, D.A.S.O.P., E.R.A. 07306, Meudon, France.The National Center for Atmospheric Research is sponsored by the National Science Foundation.