Cosmic Ray Acceleration and Transport in the Galaxy
Having arguably the most remarkable spectrum in all of physics, these energetic particles' origin remains an unsolved problem in high-energy astrophysics. The next generation of gamma-ray observatories may well provide us with a definitive answer, but this is by no means the end of the story.
The acceleration and propagation in and around their sources provide a useful laboratory for plasma physics, and act as a probe of the surrounding interstellar medium.
We use a range of different numerical approaches to study the interplay between energetic particles and the magnetised plasmas that determine their transport properties. At the extreme energies of Galactic accelerators, this requires the development of novel hybrid methods, that can handle the large separation of scales.
Using modern high power laser facilities, it is possible to isolate and diagnose microphysical processes that are known to be relevant in astrophysical settings. By comparing the relevant dimensionless quantities, it is possible in some cases, to rescale the physical processes occurring on minute laboratory scales up to vast astrophysical scales.