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Extreme ultraviolet observations of active regions in the chromosphere and the corona

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Abstract

New observations of solar active regions have been obtained by the Harvard College Observatory EUV spectroheliometer aboard the OSO-IV spacecraft. From the observations we have determined the enhancement in active regions of the emission from ions formed at various temperatures in the chromosphere and corona. The results are in accord with a simple model of active regions, for which the active region pressure is about 5 times the quiet sun pressure; the temperature gradient in the transition zone is about 5 times the quiet sun value; and the coronal temperature above active regions is slightly increased.

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Authors and Affiliations

  1. Smithsonian Astrophysical Observatory and Harvard College Observatory, Cambridge, Mass., U. S. A.

    Robert W. Noyes

  2. Harvard College Observatory, Cambridge, Mass., U. S. A.

    George L. Withbroe & Robert P. Kirshner

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  1. Robert W. Noyes
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  2. George L. Withbroe
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  3. Robert P. Kirshner
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Noyes, R.W., Withbroe, G.L. & Kirshner, R.P. Extreme ultraviolet observations of active regions in the chromosphere and the corona. Sol Phys 11, 388–398 (1970). https://doi.org/10.1007/BF00153074

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  • DOI: https://doi.org/10.1007/BF00153074

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