Estimates of terms in Ohm's law during an encounter with an electron diffusion region

Authors

Roy B. Torbert, University of New HampshireFollow
J. L. Burch, Southwest Research Institute
B. L. Giles, NASA Goddard Space Flight Center
Daniel J. Gershman, NASA Goddard Space Flight Center
C. J. Pollock, NASA Goddard Space Flight Center
J. Dorelli, NASA Goddard Space Flight Center
L. Avanov, NASA Goddard Space Flight Center
Matthew R. Argall, University of New HampshireFollow
J. R. Shuster, NASA Goddard Space Flight Center
Robert J. Strangeway, University of California
C. T. Russell, University of California
Robert E. Ergun, Laboratory for Atmospheric and Space Physics
F. Wilder, University of Colorado
K. Goodrich, University of Colorado
H. A. Faith, University of New Hampshire
Charlie J. Farrugia, University of New HampshireFollow
P. A. Lindqvist, Swedish Institute of Space Physics
T. D. Phan, University of California, Berkeley
Yu. V. Khotyaintsev, Swedish Institute of Space Physics
T. E. Moore, NASA Goddard Space Flight Center
G. T. Marklund, KTH Royal Institute of Technology
W. Daughton, Los Alamos National Laboratory
W. Magnes, Austrian Academy of Sciences
C. A. Kletzing, University of Iowa
S. Bounds, University of Iowa

Abstract

We present measurements from the Magnetospheric Multiscale (MMS) mission taken during a reconnection event on the dayside magnetopause which includes a passage through an electron diffusion region (EDR). The four MMS satellites were separated by about 10 km such that estimates of gradients and divergences allow a reasonable estimate of terms in the generalized Ohm's law, which is key to investigating the energy dissipation during reconnection. The strength and character of dissipation mechanisms determines how magnetic energy is released. We show that both electron pressure gradients and electron inertial effects are important, but not the only participants in reconnection near EDRs, since there are residuals of a few mV/m (~30–50%) of E + Ue × B (from the sum of these two terms) during the encounters. These results are compared to a simulation, which exhibits many of the observed features, but where relatively little residual is present.

Publication Date

5-28-2016

Journal Title

Geophysical Research Letters

Publisher

AGU

Digital Object Identifier (DOI)

https://dx.doi.org/10.1002/2016GL069553

Document Type

Article

Recommended Citation

Torbert, R. B.; Burch, J. L.; Giles, B. L.; Gershman, D.; Pollock, C. J.; Dorelli, J.; Avanov, L.; Argall, M. R.; Shuster, J.; Strangeway, R. J.; Russell, C. T.; Ergun, R. E.; Wilder, F. D.; Goodrich, K.; Faith, H. A.; Farrugia, C. J.; Lindqvist, P. -A.; Phan, T.; Khotyaintsev, Y.; Moore, T. E.; Marklund, G.; Daughton, W.; Magnes, W.; Kletzing, C. A.; Bounds, S. (2016). Estimates of terms in Ohm's law during an encounter with an electron diffusion region, GEOPHYSICAL RESEARCH LETTERS. Vol. 43, No. 12, 5918-5925. DOI: 10.1002/2016GL069553