Photospheric Flare Diagnositics

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The prevailing model for flare initiation is based on an electron beam that penetrates the lower atmosphere, producing explosive evaporation and heating to high temperatures. Despite numerous studies of evaporation processes in the chromosphere and corona, the impact of the flare beams to the photospheric velocity profiles has remained unexplored. The project will combine state-of-the-art simulations with observations to address important questions on the impact of flares on solar/stellar atmospheres. This project's focus on the photosphere's response to a solar flare sets it apart from previous works which have focused on the more dramatic response of the chromosphere. At this much lower height in the solar atmosphere, the effects of a flare are greatly reduced, but the observational signatures of the processes at work can be identified in spectral lines and continua across the electromagnetic spectrum. It is therefore the purpose of this project to investigate through radiative-hydrodynamic (RHD) modelling if there may be observable shifts in line spectra formed in the photosphere. Such shifts, even if on the order of m/s, are important to establish when considering exoplanet detection around distant stars to avoid false attribution of line shifts that are actually due to stellar flares. The main objectives of the project are:Use the F-CHROMA grid of flare models to identify the effects of electron beams at the deepest layers of the solar atmosphere.Expand the existing grid by including protons beams and direct heating.Perform line synthesis to identify the photospheric lines that show the strongest response to the heating.Compare the simulated spectra with high resolution spectroscopic observations.Use the simulations to define the science goals of future ground-based and space-borne observatories. These observatories include the Daniel K Inouye Solar Telescope, European Solar Telescope, Solar Orbiter and others.Other information:QUB has been a member of F-CHROMA (www.fchroma.org), a research consortium funded by the European Commission, that focused on space-based and ground-based multi-mode, multi-wavelength studies of solar flares. The student will work in collaboration with an international team of researchers at QUB, Europe and the US.Facilities to be usedRADYN & RH (Radiative Hydrodynamic Codes), Swedish Solar Telescope (La Palma), Daniel K Inouye Solar Telescope (Maui)