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Electron Beam as Origin of White-Light Solar Flares

Published online by Cambridge University Press:  12 April 2016

J. Aboudarham  and
J. C. Henoux
J. Aboudarham
Affiliation:
DASOP, Observatoire de Paris-Meudon, 92195 Meudon Principal Cedex, France
J. C. Henoux
Affiliation:
DASOP, Observatoire de Paris-Meudon, 92195 Meudon Principal Cedex, France

Abstract

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We study the effect of chromospheric bombardment by an electron beam during solar flares. Using a semi-empirical flare model, we investigate energy balance at temperature minimum level and in the upper photosphere. We show that non-thermal hydrogen ionization (i.e., due to the electrons of the beam) leads to an increase of chromospheric hydrogen continuum emission, H− population, and absorption of photo-spheric and chromospheric continuum radiation. So, the upper photosphere is radiatively heated by chromospheric continuum radiation produced by the beam. The effect of hydrogen ionization is an enhanced white-light emission both at chromospheric and photospheric level, due to Paschen and H− continua emission, respectively. We then obtain white-light contrasts compatible with observations, obviously showing the link between white-light flares and atmospheric bombardment by electron beams.

Type
Research Article
Information
International Astronomical Union Colloquium , Volume 104 , Issue 1: Solar and Stellar Flares , 1989 , pp. 19 - 30
Copyright
Copyright © Kluwer 1989

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