Electron acceleration by stochastic wave fields in a bounded plasma system

We investigate the electron acceleration dynamics in spatially stochastic wave fields. For a bounded system, the spectra (frequency and wave number) of the stochastic wave fields are discrete so that they can form spatiotemporal "singular" structures once their phases are in synchronization. As a consequence, the electrons will experience significant scattering by these singular structures, which is an in-phase effect of an ensemble of non-resonant wave-particle interactions. In the presence of parallel symmetry breaking, it is found that the governing Fokker-Planck equation has a structure similar to that of the resonant wave-particle interaction but with a broader parameter regime in the velocity/energy space of the electron distribution function.