Generalized Ohm’s Law Decomposition of the Electric Field in Magnetosheath Turbulence: Magnetospheric Multiscale Observations
Journal Article
Overview
abstract
Decomposing the electric field (E) into the contributions from; generalized Ohm’s law provides key insight into both nonlinear and; dissipative dynamics across the full range of scales within a plasma.; Using high-resolution, multi-spacecraft measurements of three intervals; in Earth’s magnetosheath from the Magnetospheric Multiscale mission, the; influence of the magnetohydrodynamic, Hall, electron pressure, and; electron inertia terms from Ohm’s law, as well as the impact of a finite; electron mass, on the turbulent spectrum are examined observationally; for the first time. The magnetohydrodynamic, Hall, and electron pressure; terms are the dominant contributions to over the accessible length; scales, which extend to scales smaller than the electron inertial length; at the greatest extent, with the Hall and electron pressure terms; dominating at sub-ion scales. The strength of the non-ideal electron; pressure contribution is stronger than expected from linear kinetic; Alfvén waves and a partial anti-alignment with the Hall electric field; is present, linked to the relative importance of electron diamagnetic; currents in the turbulence. The relative contribution of linear and; nonlinear electric fields scale with the turbulent fluctuation; amplitude, with nonlinear contributions playing the dominant role in; shaping for the intervals examined in this study. Overall, the sum of; the Ohm’s law terms and measured agree to within ~20%; across the observable scales. These results both confirm general; expectations about the behavior of in turbulent plasmas and highlight; features that should be explored further theoretically.
