Comparative Analysis of the Various Generalized Ohm's Law Terms in Magnetosheath Turbulence as Observed by Magnetospheric Multiscale

Stawarz, Julia, Matteini, L., Parashar, T. N., Franci, L., Eastwood, J. P., Gonzalez, C. A., Gingell, I. L., Burch, J. L., Ergun, R. E., Ahmadi, N., Giles, B. L., Gershman, D. J., Le Contel, O., Lindqvist, P.‐A., Russell, C. T., Strangeway, R. J. and Torbert, R. B. (2021) Comparative Analysis of the Various Generalized Ohm's Law Terms in Magnetosheath Turbulence as Observed by Magnetospheric Multiscale. Journal of Geophysical Research: Space Physics, 126 (1). 2020JA028447. ISSN 2169-9380

JGR Space Physics - 2020 - Stawarz - Comparative Analysis of the Various Generalized Ohm s Law Terms in Magnetosheath.pdf - Published Version
Available under License Creative Commons Attribution 4.0.

Download (5MB) | Preview
Official URL:


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, multispacecraft 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 E spectrum are examined observationally for the first time. The magnetohydrodynamic, Hall, and electron pressure terms are the dominant contributions to E over the accessible length scales, which extend to scales smaller than the electron gyroradius at the greatest extent, with the Hall and electron pressure terms dominating at sub-ion scales. The strength of the nonideal electron pressure contribution is stronger than expected from linear kinetic Alfvén waves and a partial antialignment 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 E for the intervals examined in this study. Overall, the sum of the Ohm's law terms and measured E agree to within ∼20% across the observable scales. These results both confirm general expectations about the behavior of E in turbulent plasmas and highlight features that should be explored further theoretically.

Item Type: Article
Additional Information: Funding information: J. E. Stawarz and J. P. Eastwood are supported by UKRI/STFC grant ST/S000364/1 and J. E. Stawarz is addi-tionally supported by the Royal Society University Research Fellowship URF\R1\201286. T. N. Parashar was partially supported by Heliophysics Guest Investigator grant 80NSSC19K0284 during this study. L. Franci is supported by UKRI/STFC grant ST/T00018X/1. I. L. Gingell is supported by the Royal Society University Research Fellow-ship URF\R1\191547.
Uncontrolled Keywords: turbulence, Magnetospheric Multiscale, generalized Ohm's law, electric field, Earth's magnetosheath
Subjects: F300 Physics
F500 Astronomy
Department: Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User: Rachel Branson
Date Deposited: 07 Dec 2022 14:29
Last Modified: 07 Dec 2022 14:30

Actions (login required)

View Item View Item


Downloads per month over past year

View more statistics