Solar flares are the most energetic explosions in the solar system. Rapid restructuring of the Sun’s coronal magnetic field results in the acceleration of particles to relativistic energies. These energetic electrons collide with the dense, underlying chromosphere, causing it to heat and expand. The resulting increase in EUV and X-ray radiation can significantly impact the upper layers of Earth’s atmosphere, as well as those of other planets. It also allows us to diagnose the plasma conditions within the flaring chromosphere and put constraints on various theoretical solar flare heating models. The study of solar flares is also important to help us understand flares on other stars, and how they may impact the search for potentially habitable exoplanets.

As Solar Cycle 24 draws to a close, we have amassed a considerable amount of solar flare data from a wealth of space-based solar observatories over the past decade. X-ray observations from the RHESSI satellite, for example, allows us to diagnose the energetic properties of accelerated (nonthermal) electrons via the thick-target bremsstrahlung process, while longer wavelength observations, from Hinode/EIS, SDO/EVE, and IRIS, etc., provide crucial information on the temperature, density, and velocity of the heated chromospheric plasma through EUV spectroscopy. This project will focus on the analysis of datasets of solar flares simultaneously observed by a range of different instruments in order to answer some of the biggest outstanding questions in solar flare physics, such as:

• What are the dominant heating and energy transport mechanisms in the solar chromosphere during solar flares, and at what depth does energy deposition take place?

• How does the energy deposited by nonthermal electrons get redistributed throughout the lower solar atmosphere, and what are the dominant energy loss mechanisms?

• How do different nonthermal electron distributions affect the geoeffective emission generated, and what are the implications for planetary atmospheres?

RHESSI, SDO (EVE+AIA), Hinode (EIS, SOT, XRT), IRIS, GOES (XRS+EUVS), MAVEN (EUM)

Funding will be provided within the studentship to allow the successful candidate to travel and present their work at national and international conferences and workshops. The successful candidate will also spend part of their time collaborating with colleagues at the NASA Goddard Space Flight Center in Greenbelt, Maryland, USA.

Dr. Ryan Milligan (QUB), Prof. Mihalis Mathioudakis (QUB), Dr. Graham Kerr (NASA/GSFC).

For more information contact the primary supervisor Dr. Ryan Milligan (r.milligan@qub.ac.uk).