In many astronomical systems, from planetary magnetospheres to clusters of galaxies, we see evidence of charged particles being accelerated to energies very much higher than those of the bulk thermal distributions in these systems. This takes the form both of direct observations (cosmic rays), observations of secondary non-thermal electromagnetic radiation (synchrotron, inverse Compton, Bremstrahlung, neutral pion decay etc) and very recently observations of high-energy secondary neutrinos. Understanding the mechanisms that accelerate these particles, and the processes by which they generate the observed secondary signals, is the aim of theoretical high-energy non-thermal astrophysics.

This work relies heavily on a combination of theoretical models and numerical simulations. It sits at the intersection of plasma physics with cosmic ray studies and high-energy astrophysics. A particular interest is the theory of diffusive shock acceleration.