Explosive energy release in solar and space plasmas

Explosive energy release in magnetically confined plasmas is a universal process, from the natural plasmas that exist in the solar system to fusion reactors such as tokamaks. From stellar atmospheres, including our own Sun, to comet tails and our own near-Earth space, these environments store magnetic energy over timescales ranging between minutes and days, which is then explosively released over far shorter timescales and converted into plasma kinetic energy. This local process has large-scale consequences for the reconfiguring the magnetic field and particle energisation. Stored energy is quickly converted into the rapid transport of bundles of magnetic flux away from the site, a variety of particle acceleration processes and the generation of electromagnetic waves. What process or processes cause this explosive energy release across each local plasma environment is still hotly debated.

We have recently discovered that there is a repeatable optical signature of the explosive energy release within Earth's environment (termed a magnetospheric substorm; Kalmoni et al., Nature Communications, 2018). With this result, we have been able to identify that unstable electromagnetic waves are inextricably linked to this energy release, solving a crucial part of a 60 year old science question of what causes this explosive energy release in the near-Earth magnetotail. Solar flares, while representing a rather different parameter regime to the Earth's magnetosphere, nevertheless display qualitatively similar repeatable optical signatures. The goal of this PhD is to build on the work done by Kalmoni et al. (2018) to investigate whether unstable electromagnetic waves are also playing a role in generating the signatures observed during the explosive energy release of solar flares. Using existing software and building upon this research framework, the student will apply the techniques developed for magnetospheric sub-storm analysis to multi-wavelength observations of solar flares, from ground and space-based platforms, with a view to determining the presence of waves and comparing their characteristics with those observed in magnetospheric sub-storms.