Supervisor: Philippa Browning
Project description: Research in solar plasma physics is concerned with modelling the complex interactions of magnetic field with plasma in the solar atmosphere, in the context of transformational new space and ground-based observations of our nearest star. There are synergies with magnetically-confined fusion plasmas, and there are opportunities for PhDs exploring both fusion and solar applications, in collaboration with Culham Centre for Fusion Energy. We are also interested in the physical processes underlying variable radio emission in young stars, building on understanding of solar flares.
A major unsolved problem is to explain why the solar coronal temperature is over a million degrees Kelvin. Coronal heating likely results from dissipation of stored magnetic energy, but the details remain controversial. A strong candidate for energy dissipation is the process of magnetic reconnection - which also operates in solar flares, and in many other space and astrophysical plasmas. One of the biggest challenges in flare physics is to explain the origin of the large numbers of high-energy electrons and ions, requiring integration of small-scale plasma kinetic models with large-scale fluid models. PhD projects are available to explore the nature and consequences of magnetic reconnection in the solar atmosphere, using magnetohydrodynamic simulations, relaxation theory, and kinetic plasma models. There is also likely to be a funded PhD project with Culham Centre for Fusion Energy studying magnetic reconnection in the core plasma of tokamaks.
The main applications are to the heating of the solar corona, and energy release and particle acceleration in solar flares. Models of energy release in unstable twisted coronal loops, and in current sheets in sheared magnetic fields, will be extended to more complex configurations, including interactions between magnetic flux ropes. Students may use a new “reduced kinetics” approach to develop self-consistent models including energetic electrons. An important aspect is “forward modelling” of observational signatures, with energetic particles potentially detected both through hard X-ray and radio emission.