Title: Electron diffusion region during magnetopause reconnection with an intermediate guide field: Magnetospheric multiscale observations

Abstract

An electron diffusion region (EDR) in magnetic reconnection with a guide magnetic field approximately 0.2 times the reconnecting component is encountered by the four Magnetospheric Multiscale spacecraft at the Earth's magnetopause. The distinct substructures in the EDR on both sides of the reconnecting current sheet are visualized with electron distribution functions that are 2 orders of magnitude higher cadence than ever achieved to enable the following new findings: (1) Motion of the demagnetized electrons plays an important role to sustain the reconnection current and contributes to the dissipation due to the nonideal electric field, (2) the finite guide field dominates over the Hall magnetic field in an electron–scale region in the exhaust and modifies the electron flow dynamics in the EDR, (3) the reconnection current is in part carried by inflowing field–aligned electrons in the magnetosphere part of the EDR, and (4) the reconnection electric field measured by multiple spacecraft is uniform over at least eight electron skin depths and corresponds to a reconnection rate of approximately 0.1. Here, the observations establish the first look at the structure of the EDR under a weak but not negligible guide field.

Authors:

Chen, L. -J.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-4768-189X"

Hesse, M. ^[2]; Wang, S.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-6783-7759"

Gershman, D.  ^[1];

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Ergun, R. E.  ^[3];

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Burch, J.  ^[4];

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• Search DOE PAGES for ORCID "0000-0003-0452-8403"

Bessho, N.  ^[1];

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Torbert, R. B.  ^[5];

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Giles, B.  ^[2];

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Webster, J. ^[6]; Pollock, C.  ^[7];

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Dorelli, J. ^[2]; Moore, T.  ^[2];

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Paterson, W.  ^[2];

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Lavraud, B.  ^[8];

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Strangeway, R.  ^[9];

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Russell, C.  ^[9];

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Khotyaintsev, Y.  ^[10];

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• Search DOE PAGES for ORCID "0000-0001-5550-3113"

Lindqvist, P. -A.  ^[11];

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Avanov, L.  ^[1]

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+ Show Author Affiliations

1. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States); Univ. of Maryland, College Park, MD (United States)
2. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)
3. Univ. of Colorado, Boulder, CO (United States)
4. Southwest Research Institute, San Antonio, TX (United States)
5. Southwest Research Institute, San Antonio, TX (United States); Univ. of New Hampshire, Durham, NH (United States)
6. Rice Univ., Houston, TX (United States)
7. Denali Scientific, Healy, AK (United States)
8. Univ. de Toulouse, Toulouse (France); Centre National de la Recherche Scientifique, Toulouse (France)
9. Univ. of California, Los Angeles, CA (United States)
10. Swedish Institute of Space Physics, Uppsala (Sweden)
11. KTH Royal Institute of Technology, Stockholm (Sweden)

Publication Date:

Fri Apr 28 00:00:00 EDT 2017

Research Org.:

Univ. of Maryland, College Park, MD (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1466266

Alternate Identifier(s):

OSTI ID: 1402346

Grant/Contract Number:  

SC0016278

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Geophysical Research. Space Physics

Additional Journal Information:

Journal Volume: 122; Journal Issue: 5; Journal ID: ISSN 2169-9380

Publisher:

American Geophysical Union

Country of Publication:

United States

Language:

English

Subject:

79 ASTRONOMY AND ASTROPHYSICS; magnetic reconnection; diffusion region; electron acceleration; electric field acceleration; electron diffusion region