Modelling of Electron and Proton Beams in a White-light Solar Flare

Ondrej Procházka, Michail Mathioudakis, Aaron Reid, Ryan Milligan, P. J. A Simoes, Joel C. Allred

Research output: Contribution to conferencePoster


Observations of an X1 class WL solar flare on 2014 June 11 showed a surprisingly weak emission in both higher order Balmer and Lyman lines and continua. The flare was observed by RHESSI but low energy cut-off of non-thermal component was indeterminable due to the unusually hard electron spectrum (delta = 3). An estimate of power in non-thermal electron beams together with an area of WL emission observed by HMI yielded to an upper and lower estimate of flux 1E9 and 3E10 erg/cm2/s, respectively. We performed a grid of models using a radiative hydrodynamic code RADYN in order to compare synthetic spectra with observations. For low energy cut-off we chose a range from 20 to 120 keV with a step of 20 keV and delta parameter equal to 3. Electron beam-driven models show that higher low energy cut-off is more likely to produce an absorption Balmer line profile, if the total energy flux remains relatively low. On the other hand a detectable rise of HMI continuum (617 nm) lays a lower limit on the beam flux. Proton beam-driven models with equivalent fluxes indicate a greater penetration depth, while the Balmer lines reveal significantly weaker emission. Atmospheric temperature profiles show that for higher values of low energy cut-off the energy of the beam is deposited lower in chromosphere or even in temperature minimum region. This finding suggests, that suppressed hydrogen emission can indicate a formation of white-light continuum below chromosphere.
Original languageEnglish
Publication statusPublished - 14 Dec 2017
EventAmerican Geophysical Union Fall Meeting 2017 - New Orleans, United States
Duration: 11 Dec 201715 Dec 2017


ConferenceAmerican Geophysical Union Fall Meeting 2017
Abbreviated titleAGU 2017
Country/TerritoryUnited States
CityNew Orleans


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