Modeling the turbulent cross-helicity dissipation rate

Abstract

   It has been recognized that the turbulent cross helicity (correlation between the velocity and magnetic-field fluctuations) can play an important role in several magnetohydrodynamic (MHD) plasma phenomena such as the global magnetic-field generation, the turbulence suppression, etc. Despite its relevance to the cross-helicity evolution, little attention has been given to the dissipation rate of the turbulent cross helicity. In this paper, we consider the dissipation rate of the turbulent cross helicity and propose an algebraic model and an evolution equation of the cross-helicity dissipation rate (eW equation). We apply the model to the solar-wind turbulence, where several observations have been made on the turbulent cross helicity, and validate the model of cross-helicity dissipation. It is shown that, as far as the solar-wind application is concerned, the simplest possible algebraic model is useful enough to elucidate the spatial evolution of the solar-wind turbulence. [This abstract is not included in the PDF]