Reproducing type II white-light solar flare observations with electron and proton beam simulations

Procházka, O., Reid, A., Milligan, R. O. , Simões, P. J.A. , Allred, J. C. and Mathioudakis, M. (2018) Reproducing type II white-light solar flare observations with electron and proton beam simulations. Astrophysical Journal, 862(1), 76. (doi: 10.3847/1538-4357/aaca37)

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We investigate the cause of the suppressed Balmer series and the origin of the white-light continuum emission in the X1.0 class solar flare on 2014 June 11. We use radiative hydrodynamic simulations to model the response of the flaring atmosphere to both electron and proton beams, which are energetically constrained using Ramaty High Energy Solar Spectroscopic Imager and Fermi observations. A comparison of synthetic spectra with the observations allows us to narrow the range of beam fluxes and low energy cutoff that may be applicable to this event. We conclude that the electron and proton beams that can reproduce the observed spectral features are those that have relatively low fluxes and high values for the low energy cutoff. While electron beams shift the upper chromosphere and transition region to greater geometrical heights, proton beams with a similar flux leave these areas of the atmosphere relatively undisturbed. It is easier for proton beams to penetrate to the deeper layers and not deposit their energy in the upper chromosphere where the Balmer lines are formed. The relatively weak particle beams that are applicable to this flare do not cause a significant shift of the τ = 1 surface and the observed excess WL emission is optically thin.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Simoes, Dr Paulo and Milligan, Dr Ryan
Authors: Procházka, O., Reid, A., Milligan, R. O., Simões, P. J.A., Allred, J. C., and Mathioudakis, M.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Astrophysical Journal
Publisher:American Astronomical Society
ISSN (Online):1538-4357
Published Online:24 July 2018
Copyright Holders:Copyright © 2018 The American Astronomical Society
First Published:First published in Astrophysical Journal 862(1): 76
Publisher Policy:Reproduced under a Creative Commons License
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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
595181Chromospheric Flares: Observations, Models and Archives (CHROMA)Lyndsay FletcherEuropean Commission (EC)606862P&A - PHYSICS & ASTRONOMY
718451Modelling and Multi-wavelength Observations of Solar Flare HeatingRyan MilliganScience & Technology Facilities Council (STFC)ST/N004981/1S&E P&A - PHYSICS & ASTRONOMY