Plasmas so hot that their temperature is a significant fraction of the electron rest mass are ubiquitous in high-energy astrophysics and are becoming increasingly accessible in the laboratory. My research is concerned with the fundamental interactions that take place in these systems.
Firstly, at these temperatures pair production can become prolific due to the Breit-Wheeler process — the formation of an electron-positron pair in the collision of two photons. Despite being the simplest way by which pure light can be converted into matter, this has never been directly observed in the laboratory. Our recent work has shown how existing high-energy density physics (HEDP) facilities — traditionally used in fusion energy research — can be used to detect this process for the first time. For more information see our paper; for examples of media coverage see the Guardian and BBC News articles.
In addition, electrons move relativistically at high temperatures, affecting the nature of their mutual Coulomb interaction. This impacts the rate of slowing of fast particles, as well as electrical and heat transport in systems ranging from inertial fusion targets and tokamaks to high-temperature astrophysical plasmas. We have recently extended the basic results of kinetic theory to account for these relativistic effects.
High temperature plasmas are inherently linked with fusion energy research. Along with others in the HEDP group at Imperial, I am involved in modelling the kinetics of systems relevant to inertial confinement fusion.
Pike OJ, Rose SJ, 2016, Transport coefficients of a relativistic plasma, Physical Review E, Vol:93, ISSN:1539-3755
et al., 2014, A photon-photon collider in a vacuum hohlraum, Nature Photonics, Vol:8, ISSN:1749-4885, Pages:434-436
Pike OJ, Rose SJ, 2014, Dynamical friction in a relativistic plasma, Physical Review E, Vol:89, ISSN:1539-3755