Turbulent Cascade at 1 AU in High Cross-Helicity Flows

Analysis of the scaling of the mixed third moments of velocity and magnetic fluctuations in the solar wind plasma, and the energy cascade rates derived from the scaling, reveal a strong dependence on the amount of cross-field correlation between the velocity and magnetic field fluctuations. When the correlation is greater than about 75%, the cascade rate of the outward-propagating (majority) component, and of the total energy and the cross-helicity are surprisingly negative. This indicates a back transfer of energy from small to large scales within the inertial range of the dominant outward-propagating component. It is clear that the transfer of energy acts to reinforce the dominance of the outward-propagating (majority) component and may explain, in part, the persistent observations of large cross-field correlations that have been a defining aspect of solar wind physics for almost 40 years.