Turbulent E×B advection of charged test particles with large gyroradii

Abstract

The turbulent E×B advection of charged test particles with large gyroradii is investigated. To this aim, a recently developed theory—the so-called decorrelation trajectory method—is used together with direct numerical simulations and analytical calculations. It is found that for Kubo numbers larger than about unity, the particle diffusivity is almost independent of the gyroradius as long as the latter does not exceed the correlation length of the electrostatic potential. The underlying physical mechanisms leading to this surprising and initially counterintuitive behavior are identified.