Electron Energy Density Dissipation Rate and Turbulent Cascade Rate in the Terrestrial Magnetosheath

Abstract:

The burst-mode electromagnetic fields and particle velocity distribution data from the Magnetospheric Multiscale (MMS) mission allow for an unprecedented temporal resolution of turbulence in the terrestrial magnetosheath. Using the Field Particle Correlation (FPC) technique, we analyze data from quiescent turbulent magnetosheath intervals through correlating the parallel electric field from the Electric Field Double Probes with the electron velocity distributions from the Fast Plasma Investigation’s Dual Electron Spectrometers. The FPC allows us to identify velocity-space signatures of electron Landau damping, and calculate the electron energy density dissipation rate. In the intervals analyzed, the velocity-space signatures indicate the presence of Landau damping of turbulent energy, as well as strong damping of waves traveling either parallel or anti-parallel to the ambient magnetic field yielding an asymmetric signature. This directionality of wave damping is examined through the Poynting energy flux. In addition, we make a comparison between the electron energy density dissipation rate and the theoretical turbulent energy cascade rate and find that Landau damping is often the mechanism responsible for the dissipation of turbulent energy in the magnetosheath.