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Radio Observations of Coronal Holes

Published online by Cambridge University Press:  14 August 2015

K. V. Sheridan  and
G. A. Dulk
K. V. Sheridan
Affiliation:
Division of Radiophysics, CSIRO, Sydney, Australia
G. A. Dulk
Affiliation:
Also Department of Astro-Geophysics, University of Colorado, Boulder, U.S.A.

Abstract

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Coronal holes have been observed on several occasions with the 80 and 160 MHz radioheliograph at Culgoora. At 160 MHz the holes invariably appear as areas of low brightness, either on the disk or at the limb. At 80 MHz holes on the limb always appear less bright than their surroundings but on the disk they frequently appear brighter.

The simplest interpretation is that the coronal temperature in holes near the 80 MHz critical density (8 × 107 cm−3) is higher than in normal quiet regions, but that the density at this level is lower.

Type
Part I. The Life History of Coronal Structures and Fields
Information
Symposium - International Astronomical Union , Volume 91: Solar and Interplanetary Dynamics , 1980 , pp. 37 - 43
Copyright
Copyright © Reidel 1980 

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