Using observational data from the emph{Magnetospheric Multiscale} (MMS) Mission in the Earths magnetosheath, we estimate the energy cascade rate using different techniques within the framework of incompressible magnetohydrodynamic (MHD) turbulence. At the energy containing scale, the energy budget is controlled by the von Karman decay law. Inertial range cascade is estimated by fitting a linear scaling to the mixed third-order structure function. Finally, we use a multi-spacecraft technique to estimate the Kolmogorov-Yaglom-like cascade rate in the kinetic range, well below the ion inertial length scale. We find that the inertial range cascade rate is almost equal to the one predicted by the von Karman law at the energy containing scale, while the cascade rate evaluated at the kinetic scale is somewhat lower, as anticipated in theory~citep{Yang2017PoP}. Further, in agreement with a recent study~citep{Hadid2018PRL}, we find that the incompressive cascade rate in the Earths magnetosheath is about $1000$ times larger than the cascade rate in the pristine solar wind.
تحميل البحث