Dispersive Effects of Hall Electric Field in Turbulence.

A familiar feature of turbulence in a low collisionality turbulence is an increase in the electric field spectrum, relative to the magnetic field spectrum, at wavenumbers near the reciprocal of the ion inertial scale. This effect is commonly observed in the solar wind. Here we examine this feature numerically, using a variety of simulations, including compressible Hall MHD, incompressible Hall MHD, and one-, two-, and three-dimensional cases. A feature of this type is even found in a statistical Hall MHD model with no dissipation. This leads to the conclusion that the only requirement for obtaining this dispersive effect is the Hall term in the generalized Ohm’s law. Therefore this observation does not distinguish between whistler and kinetic Alfvén waves, between waves and turbulence, nor even between fluid and kinetic plasma models. [ABSTRACT FROM AUTHOR]