Perpendicular ion heating in turbulence and reconnection: magnetic moment breaking by coherent fluctuations

arXiv:2509.05518v1 Announce Type: new
Abstract: We study the interaction of an ion with a fluctuation in the electromagnetic fields that is localized 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 timescale of the electromagnetic fluctuation. This leads to diffusion in energy in both $v_perp$ and $v_parallel$. We show how to apply our results to general plasma physics phenomena, and specifically to Alfv’enic 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.