Whistler turbulence at variable electron beta: Three-dimensional particle-in-cell simulations

Three-dimensional particle-in-cell (PIC) simulations of whistler turbulence at three different initial values of (e) are carried out on a collisionless, homogeneous, magnetized plasma model. The simulations begin with an initial ensemble of relatively long-wavelength whistler modes and follow the temporal evolution of the fluctuations as wave-wave interactions lead to a forward cascade into a broadband, turbulent spectrum at shorter wavelengths with a wave vector anisotropy in the sense of k>k(vertical bar). Here and vertical bar denote directions perpendicular and parallel to the background magnetic field, respectively. In addition, wave-particle interactions lead to fluctuating field dissipation and electron heating with a temperature anisotropy in the sense of T-vertical bar>T. At early times, the wave-wave cascade dominates energy transport, whereas wave-particle Landau damping dominates at late simulation times. Larger values of (e) correspond to a faster forward cascade in wave number and to a faster rate of electron heating, as well as to a less anisotropic wave vector distribution and to a less anisotropic electron velocity distribution.