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Author Procházka, Ondrej ♦ Milligan, Ryan O. ♦ Mathioudakis, Mihalis ♦ Allred, Joel C. ♦ Kowalski, Adam F. ♦ Kotrč, Pavel
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword ASTROPHYSICS, COSMOLOGY AND ASTRONOMY ♦ CHROMOSPHERE ♦ ELECTRON BEAMS ♦ EMISSION ♦ ENERGY ABSORPTION ♦ ENERGY LOSSES ♦ GAMMA RADIATION ♦ HARD X RADIATION ♦ HYDRODYNAMICS ♦ HYDROGEN ♦ LAYERS ♦ LYMAN LINES ♦ PHOTOSPHERE ♦ SIMULATION ♦ SOLAR FLARES ♦ SUN ♦ VISIBLE RADIATION ♦ X-RAY SPECTRA
Abstract We present unique NUV observations of a well-observed X-class flare from NOAA 12087 obtained at the Ondřejov Observatory. The flare shows a strong white-light continuum but no detectable emission in the higher Balmer and Lyman lines. Reuven Ramaty High-Energy Solar Spectroscopic Imager and Fermi observations indicate an extremely hard X-ray spectrum and γ -ray emission. We use the RADYN radiative hydrodynamic code to perform two types of simulations: one where an energy of 3 × 10{sup 11} erg cm{sup −2} s{sup −1} is deposited by an electron beam with a spectral index of ≈3, and a second where the same energy is applied directly to the photosphere. The combination of observations and simulations allows us to conclude that the white-light emission and the suppression or complete lack of hydrogen emission lines is best explained by a model where the dominant energy deposition layer is located in the lower layers of the solar atmosphere, rather than the chromosphere.
ISSN 0004637X
Educational Use Research
Learning Resource Type Article
Publisher Date 2017-03-01
Publisher Place United States
Journal Astrophysical Journal
Volume Number 837
Issue Number 1


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