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Radio Wavelength Observations: Structure, Strength and Variability of Magnetic Fields in the Transition Region and the Solar Corona

Published online by Cambridge University Press:  04 August 2017

Kenneth R. Lang
Kenneth R. Lang*
Affiliation:
Department of Physics, Tufts University, Medford, MA 02155, USA

Abstract

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The 6 cm radiation of solar active regions marks the legs of dipolar loops which have their footpoints in lower-lying sunspots. The temperatures T ≈ 106K and longitudinal magnetic field strengths Hℓ ≈ 600 Gauss at heights h ≈ 4 × 109 cm above sunspot umbrae. The circularly polarized emission at 6 cm delineates the magnetic structure above sunspot penumbrae. The 20 cm radiation of solar active regions delineates the ubiquitous coronal loops previously detected at X-ray wavelengths. We infer semilengths L ≈ 5 × 109cm, maximum electron temperatures Te(max) ≈ 3 × 106K, emission measures and electron densities Ne ≈ 109cm−3 for the 20 cm bremsstrahlung. Future V.L.A. observations at 20 cm may be used to determine the magnetic field strength of coronal loops. Changes in temperature and magnetic structure before and during solar bursts are briefly discussed.

Type
IV. The Role of Magnetic Fields in the Structure and Energy Balance of Stellar Atmospheres
Information
Symposium - International Astronomical Union , Volume 102: Solar and Stellar Magnetic Fields: Origins and Coronal Effects , 1983 , pp. 363 - 367
Copyright
Copyright © Reidel 1983 

References

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