Electron and Ion Heating By Whistler Turbulence: Three-Dimensional Particle-in-Cell Simulations

Abstract:

Three-dimensional particle-in-cell (PIC) simulations of whistler turbulence in a magnetized, homogeneous, collisionless plasma have been carried out to study the consequent heating of both electrons and ions. An initial relatively isotropic spectrum of long-wavelength whistler mode fluctuations is imposed upon the system. The simulations follow the temporal evolution of the field fluctuations as they decay via a forward cascade into a broadband, turbulent spectrum at shorter wavelengths with an anisotropy in the sense of stronger fluctuation energy at k_||, where the subscripts denote directions relative to the background magnetic field. As in previous whistler turbulence PIC simulations, electrons are heated with T_||e >> T_perp,e.  Consistent with the results of Saito and Nariyuki (2014) the ions are also heated, although more weakly than the electrons and with T_perp,i >> T_||i. Larger simulation box sizes enable longer wavelength turbulence and lead to comparatively greater ion heating. Ion heating as a function of β_e and initial fluctuation amplitudes is also studied.

 Saito, S., and Y. Nariyuki (2014), Perpendicular Ion Acceleration in Whistler Turbulence, Phys. Plasmas, 21, 042303.