Ion‐scale structure in Mercury's magnetopause reconnection diffusion region

Abstract The strength and time dependence of the electric field in a magnetopause diffusion region relate to the rate of magnetic reconnection between the solar wind and a planetary magnetic field. Here we use ~150 ms measurements of energetic electrons from the Mercury Surface, Space Environment, G...

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Main Authors: Daniel J. Gershman, John C. Dorelli, Gina A. DiBraccio, Jim M. Raines, James A. Slavin, Gangkai Poh, Thomas H. Zurbuchen
Format: Article
Language:English
Published: Wiley 2016-06-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1002/2016GL069163
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author Daniel J. Gershman
John C. Dorelli
Gina A. DiBraccio
Jim M. Raines
James A. Slavin
Gangkai Poh
Thomas H. Zurbuchen
author_facet Daniel J. Gershman
John C. Dorelli
Gina A. DiBraccio
Jim M. Raines
James A. Slavin
Gangkai Poh
Thomas H. Zurbuchen
author_sort Daniel J. Gershman
collection DOAJ
description Abstract The strength and time dependence of the electric field in a magnetopause diffusion region relate to the rate of magnetic reconnection between the solar wind and a planetary magnetic field. Here we use ~150 ms measurements of energetic electrons from the Mercury Surface, Space Environment, GEochemistry, and Ranging (MESSENGER) spacecraft observed over Mercury's dayside polar cap boundary (PCB) to infer such small‐scale changes in magnetic topology and reconnection rates. We provide the first direct measurement of open magnetic topology in flux transfer events at Mercury, structures thought to account for a significant portion of the open magnetic flux transport throughout the magnetosphere. In addition, variations in PCB latitude likely correspond to intermittent bursts of ~0.3–3 mV/m reconnection electric fields separated by ~5–10 s, resulting in average and peak normalized dayside reconnection rates of ~0.02 and ~0.2, respectively. These data demonstrate that structure in the magnetopause diffusion region at Mercury occurs at the smallest ion scales relevant to reconnection physics.
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institution DOAJ
issn 0094-8276
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publishDate 2016-06-01
publisher Wiley
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series Geophysical Research Letters
spelling doaj-art-94f8dfeab09040129c6100310403cbbd2025-08-20T03:10:24ZengWileyGeophysical Research Letters0094-82761944-80072016-06-0143125935594210.1002/2016GL069163Ion‐scale structure in Mercury's magnetopause reconnection diffusion regionDaniel J. Gershman0John C. Dorelli1Gina A. DiBraccio2Jim M. Raines3James A. Slavin4Gangkai Poh5Thomas H. Zurbuchen6Department of Astronomy University of Maryland College Park Maryland USANASA Goddard Space Flight Center Greenbelt Maryland USANASA Goddard Space Flight Center Greenbelt Maryland USAClimate and Space Sciences and Engineering University of Michigan Ann Arbor Michigan USAClimate and Space Sciences and Engineering University of Michigan Ann Arbor Michigan USAClimate and Space Sciences and Engineering University of Michigan Ann Arbor Michigan USAClimate and Space Sciences and Engineering University of Michigan Ann Arbor Michigan USAAbstract The strength and time dependence of the electric field in a magnetopause diffusion region relate to the rate of magnetic reconnection between the solar wind and a planetary magnetic field. Here we use ~150 ms measurements of energetic electrons from the Mercury Surface, Space Environment, GEochemistry, and Ranging (MESSENGER) spacecraft observed over Mercury's dayside polar cap boundary (PCB) to infer such small‐scale changes in magnetic topology and reconnection rates. We provide the first direct measurement of open magnetic topology in flux transfer events at Mercury, structures thought to account for a significant portion of the open magnetic flux transport throughout the magnetosphere. In addition, variations in PCB latitude likely correspond to intermittent bursts of ~0.3–3 mV/m reconnection electric fields separated by ~5–10 s, resulting in average and peak normalized dayside reconnection rates of ~0.02 and ~0.2, respectively. These data demonstrate that structure in the magnetopause diffusion region at Mercury occurs at the smallest ion scales relevant to reconnection physics.https://doi.org/10.1002/2016GL069163reconnectionkinetic plasmaMercurypolar capflux transfer eventflux rope
spellingShingle Daniel J. Gershman
John C. Dorelli
Gina A. DiBraccio
Jim M. Raines
James A. Slavin
Gangkai Poh
Thomas H. Zurbuchen
Ion‐scale structure in Mercury's magnetopause reconnection diffusion region
Geophysical Research Letters
reconnection
kinetic plasma
Mercury
polar cap
flux transfer event
flux rope
title Ion‐scale structure in Mercury's magnetopause reconnection diffusion region
title_full Ion‐scale structure in Mercury's magnetopause reconnection diffusion region
title_fullStr Ion‐scale structure in Mercury's magnetopause reconnection diffusion region
title_full_unstemmed Ion‐scale structure in Mercury's magnetopause reconnection diffusion region
title_short Ion‐scale structure in Mercury's magnetopause reconnection diffusion region
title_sort ion scale structure in mercury s magnetopause reconnection diffusion region
topic reconnection
kinetic plasma
Mercury
polar cap
flux transfer event
flux rope
url https://doi.org/10.1002/2016GL069163
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AT johncdorelli ionscalestructureinmercurysmagnetopausereconnectiondiffusionregion
AT ginaadibraccio ionscalestructureinmercurysmagnetopausereconnectiondiffusionregion
AT jimmraines ionscalestructureinmercurysmagnetopausereconnectiondiffusionregion
AT jamesaslavin ionscalestructureinmercurysmagnetopausereconnectiondiffusionregion
AT gangkaipoh ionscalestructureinmercurysmagnetopausereconnectiondiffusionregion
AT thomashzurbuchen ionscalestructureinmercurysmagnetopausereconnectiondiffusionregion