Fast magnetic and turbulent-wave dynamos in electron magnetohydrodynamics

The influence of inertia on the spontaneous amplification of large-scale perturbations by electron magnetohydrodynamic (EMHD) turbulence is studied in a 2 1/2 -dimensional(2 1/2 -D) model. It is shown that electron inertia results in the modification of ct-like effects, which are due to the helicity of the turbulence. Under some conditions no instability of the mean field due to helicity of turbulence will occur. Electron inertia can also change the sign of turbulent viscosity in the equation of the third component of the mean held, making it negative. The possibility is discussed of the generation of 3-D whistlers by 2-D EMHD turbulence due to either helicity or to anisotropy of the turbulence. Unlike the case of 2-D large-scale perturbations, turbulent resistivity is anisotropic and leads to the destabilization of whistler modes, independently of the sign of the resistivity coefficient. (C) 2000 Elsevier Science Ltd. All rights reserved.