Scale-dependent energy transfer and conversion in anisotropic compressible space and astrophysical plasma turbulence*

The cross-scale transfer of kinetic and magnetic energy is an important process in plasma turbulence. For compressible magnetized plasmas that are typically found in space and astrophysical environments, the turbulence can be highly anisotropic with respect to the background magnetic field and the energy transfer parallel and perpendicular to the magnetic field needs to be considered separately. While local interactions dominate the cross-scale energy transfer in typical isotropic turbulence, the locality of energy transfer in anisotropic turbulence remains poorly understood. We present a spatial filtering technique to calculate various scale-dependent energy transfer and conversion terms such as kinetic, magnetic and pressure dilatation processes. The analysis presented here allows us to compute the anisotropic cross-scale energy fluxes and demonstrate their locality (or nonlocality) in 3D compressible MHD simulations of turbulence. Our results shed light on the role turbulence plays in the solar wind heating and the transport of energetic particles.