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Lyman continuum observations of solar flaresA study is made of Lyman continuum observations of solar flares, using data obtained by the EUV spectroheliometer on the Apollo Telescope Mount. It is found that there are two main types of flare regions: an overall 'mean' flare coincident with the H-alpha flare region, and transient Lyman continuum kernels which can be identified with the H-alpha and X-ray kernels observed by other authors. It is found that the ground level hydrogen population in flares is closer to LTE than in the quiet sun and active regions, and that the level of Lyman continuum formation is lowered in the atmosphere from a mass column density .000005 g/sq cm in the quiet sun to .0003 g/sq cm in the mean flare, and to .001 g/sq cm in kernels. From these results the amount of chromospheric material 'evaporated' into the high temperature region is derived, which is found to be approximately 10 to the 15th g, in agreement with observations of X-ray emission measures.
Document ID
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Machado, M. E.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Noyes, R. W.
(Harvard College Observatory and Smithsonian Astrophysical Observatory, Center for Astrophysics, Cambridge Mass., United States)
Date Acquired
August 9, 2013
Publication Date
September 1, 1978
Publication Information
Publication: Solar Physics
Volume: 59
Subject Category
Solar Physics
Accession Number
Funding Number(s)
Distribution Limits

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