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 is generally quantified by the dissipation rate in the small dissipation range, along with the third-order law in the inertial range. To investigate the local properties of the energy transfer process, here we employ three main diagnostics: the locally averaged dissipation rate  ε_r at different scales r, the local energy transfer (LET) rate, and the scale-filtered energy flux. The direct numerical simulation of three-dimensional incompressible magnetohydrodynamic (MHD) turbulence is conducted. Preliminary results include: (i) the spatial distributions of these energy transfer diagnostics show scale dependence, which also suggests that these diagnostics dominate at different scales; and (ii) even though these diagnostics could not be pointwise correlated, they exhibit similar patterns. To further quantify their correlation, we calculated the correlation functions, which show that the energy dissipation rate, the LET, and the scale-filtered energy flux have regional correlation, that is, they occur in close proximity to each other. Further analyses shall be conducted from several aspects: (i) taking into account the anisotropic effect on the energy transfer process, and (ii) extending into kinetic systems, wherein kinetic particle-in-cell (PIC) simulations shall be used, and the energy conversion channels, such as pressure-strain interaction and electromagnetic work, will be employed.