Statistics of locally averaged energy transfer rate in plasma turbulence

Energy transfer across scales is essential for understanding the dissipation and heating of plasma turbulence. In the energy cascade scenario, the energy transfer rate can be assessed through the third-order law in the inertial range, and it is directly related to the rate of dissipation occurring at the small scale. To investigate the local properties of the energy transfer process, here, we employ three main diagnostics: the locally averaged dissipation rate

at different scales

r r $r$

, the local energy transfer (LET) rate and the scale-filtered energy flux. The analyses are performed on direct numerical simulations of three-dimensional (3-D) incompressible magnetohydrodynamic (MHD) turbulence to evaluate these diagnostics. The outcomes of our study include: (i) an assessment of the spatial distribution of energy transfer rates across scales to determine which diagnostic best captures the features of energy transfer in different ranges; and (ii) a comparison of the outputs of the different diagnostics at significant scales, including a quantitative evaluation of their correlation using appropriate correlation coefficients. The latter shows that the energy dissipation rate, the LET and the scale-filtered energy flux have regional correlation, that is, although not exactly co-located, the intense regions of these three diagnostics occur in spatial proximity. Our results provide insights into understanding the energy transfer process in MHD and plasma turbulence, which shall be extended to more realistic systems.