Energy dissipation by whistler turbulence: Three-dimensional particle-in-cell simulations

Three-dimensional particle-in-cell simulations of whistler turbulence are carried out on a collisionless, homogeneous, magnetized plasma model. The simulations use an initial ensemble of relatively long wavelength whistler modes and follow the temporal evolution of the fluctuations as they cascade into a broadband, anisotropic, turbulent spectrum at shorter wavelengths. For relatively small levels of the initial fluctuation energy ϵe, linear collisionless damping provides most of the dissipation of the turbulence. But as ϵe and the total dissipation increase, linear damping becomes less important and, especially at βe ≪ 1, nonlinear processes become stronger. The PDFs and kurtoses of the magnetic field increments in the simulations suggest that intermittency in whistler turbulence generally increases with increasing ϵe and βe. Correlation coefficient calculations imply that the current structure dissipation also increases with increasing ϵe and βe, and that the nonlinear dissipation processes in these simulations are primarily associated with regions of localized current structures