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The Structure of Solar Active Regions from EUV and Soft X-Ray Observations

Published online by Cambridge University Press:  14 August 2015

Carole Jordan
Carole Jordan*
Affiliation:
Center for Astrophysics, Harvard College Observatory and Smithsonian Astrophysical Observatory, Cambridge, Mass. 02138, U.S.A.

Abstract

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The structure of solar active regions derived from EUV and soft X-ray observations is reviewed. The methods by which the emission measure as a function of temperature can be interpreted are discussed. The models of density and temperature which can be made from a variety of combinations of the emission measure with information on the spatial distribution of material, are broadly consistent. They show that the plasma at low heights over the central parts of an active region is hotter and denser than that which extends to greater heights. It appears that much of the emitting material exists in the form of loop structures, presumably magnetically controlled flux tubes. Analytical relationships between the physically important parameters describing the properties of the active region at Te > 2 × 105 K are developed and discussed.

Type
Part 2: Active Regions
Information
Symposium - International Astronomical Union , Volume 68: Solar X, Gamma, and EUV Radiation , 1975 , pp. 109 - 131
Copyright
Copyright © Reidel 1975 

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