Observations of turbulence in a Kelvin-Helmholtz event on September 8, 2015 by the Magnetospheric Multiscale Mission

Abstract

Spatial and high-time-resolution properties of the velocities, magnetic eld, and 3D electric eld within plasma turbulence are examined observationally using data from the Magnetospheric Multiscale Mission. Observations from a Kelvin-Helmholtz instability (KHI) on the Earth's magnetopause are examined, which both provides a series of repeatable intervals to analyze, giving better statistics, and provides a rst look at the properties of turbulence in the KHI. For the rst time direct observations of both the high-frequency ion and electron velocity spectra are examined, showing differing ion and electron behavior at kinetic scales. Temporal spectra ex-hibit power law behavior with changes in slope near the ion gyrofrequency and lower-hybrid frequency. The work provides the rst observational evi- dence for turbulent intermittency and anisotropy consistent with quasi-two-dimensional turbulence in association with the KHI. The behavior of kinetic scale intermittency is found to have di erences from previous studies of solar wind turbulence, leading to novel insights on the turbulent dynamics in the KHI