Measurement of the Magnetic Reconnection Rate in the Earth's Magnetotail

T. K.M. Nakamura, K. J. Genestreti, Y. H. Liu, R. Nakamura, Teh Wai Leong, H. Hasegawa, W. Daughton, M. Hesse, R. B. Torbert, J. L. Burch, B. L. Giles

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

In the Earth's magnetotail, magnetic reconnection releases stored magnetic energy and drives magnetospheric convection. The rate at which magnetic flux is transferred from the reconnection inflow to outflow regions is determined by the reconnection electric field Er, which is often referred to as the unnormalized reconnection rate. To better quantify the efficiency of reconnection, this electric field Er is often normalized by the characteristic Alfvén speed and the reconnecting magnetic field. This parameter is generally called the normalized or dimensionless reconnection rate R. In this paper, we employ a two-dimensional fully kinetic simulation to model a magnetotail reconnection event with weak geomagnetic activity (<200 nT of the AE index) observed by the Magnetospheric Multiscale (MMS) mission on 11 July 2017. We obtain R and Er from direct measurements in the diffusion region and indirect measurements of the rate at the separatrix using a recently proposed remote sensing technique. The measured normalized rate for this MMS event is R ∼0.15–0.2, consistent with theoretical and simulation models of fast collisionless reconnection. This corresponds to an unnormalized rate of Er ∼2–3 mV/m. Based on quantitative consistencies between the simulation and the MMS observations, we conclude that our estimates of the reconnection rates are reasonably accurate. Given that past studies have found Er of the order ∼10 mV/m during strong geomagnetic substorms, these results indicate that the local Er in magnetotail reconnection may be an important parameter controlling the amplitude of geomagnetic disturbances.

Original languageEnglish
Pages (from-to)9150-9168
Number of pages19
JournalJournal of Geophysical Research: Space Physics
Volume123
Issue number11
DOIs
Publication statusPublished - 1 Nov 2018

Fingerprint

geomagnetic tail
magnetotail
electric field
Earth (planet)
Electric fields
Magnetic flux
magnetic fields
remote sensing
Remote sensing
simulation models
Magnetic fields
magnetotails
kinetics
Kinetics
energy
simulation
electric fields
rate
magnetic flux
methodology

Keywords

  • geomagnetic activity
  • magnetic reconnection
  • magnetotail
  • MMS
  • PIC simulation
  • reconnection rate

ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Space and Planetary Science
  • Earth and Planetary Sciences (miscellaneous)
  • Palaeontology

Cite this

Nakamura, T. K. M., Genestreti, K. J., Liu, Y. H., Nakamura, R., Wai Leong, T., Hasegawa, H., ... Giles, B. L. (2018). Measurement of the Magnetic Reconnection Rate in the Earth's Magnetotail. Journal of Geophysical Research: Space Physics, 123(11), 9150-9168. https://doi.org/10.1029/2018JA025713

Measurement of the Magnetic Reconnection Rate in the Earth's Magnetotail. / Nakamura, T. K.M.; Genestreti, K. J.; Liu, Y. H.; Nakamura, R.; Wai Leong, Teh; Hasegawa, H.; Daughton, W.; Hesse, M.; Torbert, R. B.; Burch, J. L.; Giles, B. L.

In: Journal of Geophysical Research: Space Physics, Vol. 123, No. 11, 01.11.2018, p. 9150-9168.

Research output: Contribution to journalArticle

Nakamura, TKM, Genestreti, KJ, Liu, YH, Nakamura, R, Wai Leong, T, Hasegawa, H, Daughton, W, Hesse, M, Torbert, RB, Burch, JL & Giles, BL 2018, 'Measurement of the Magnetic Reconnection Rate in the Earth's Magnetotail', Journal of Geophysical Research: Space Physics, vol. 123, no. 11, pp. 9150-9168. https://doi.org/10.1029/2018JA025713
Nakamura, T. K.M. ; Genestreti, K. J. ; Liu, Y. H. ; Nakamura, R. ; Wai Leong, Teh ; Hasegawa, H. ; Daughton, W. ; Hesse, M. ; Torbert, R. B. ; Burch, J. L. ; Giles, B. L. / Measurement of the Magnetic Reconnection Rate in the Earth's Magnetotail. In: Journal of Geophysical Research: Space Physics. 2018 ; Vol. 123, No. 11. pp. 9150-9168.
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