Alfred Mallet, K. G. Klein, Benjamin D. G. Chandran, Tamar Ervin, Trevor A. Bowen
We study the interaction of an ion with a fluctuation in the electromagnetic fields that is localised in both space and time. We study the scale dependence of the interaction in both space and time, deriving a generic form for the ion's energy change, which involves an exponential cutoff based on the characteristic time scale of the electromagnetic fluctuation. This leads to diffusion in energy in both and . We show how to apply our results to general plasma physics phenomena, and specifically to Alfvénic turbulence and to reconnection. Our theory can be viewed as a unification of previous models of stochastic ion heating, cyclotron heating and reconnection heating in a single theoretical framework.