Magnetospheric Multiscale Observations of the Electron Diffusion Region of Large Guide Field Magnetic Reconnection

S Eriksson; F D Wilder; R E Ergun; S J Schwartz; P A Cassak; J L Burch; L-J Chen; R B Torbert; T D Phan; B Lavraud; K A Goodrich; J C Holmes; J E Stawarz; A P Sturner; D M Malaspina; M E Usanova; K J Trattner; R J Strangeway; C T Russell; C J Pollock; B L Giles; M Hesse; P-A Lindqvist; J F Drake; M A Shay; R Nakamura; G T Marklund

doi:10.1103/PhysRevLett.117.015001

Magnetospheric Multiscale Observations of the Electron Diffusion Region of Large Guide Field Magnetic Reconnection

Phys Rev Lett. 2016 Jul 1;117(1):015001. doi: 10.1103/PhysRevLett.117.015001. Epub 2016 Jul 1.

Authors

S Eriksson¹, F D Wilder¹, R E Ergun^{1

2}, S J Schwartz^{1

3}, P A Cassak⁴, J L Burch⁵, L-J Chen⁶, R B Torbert^{5

7}, T D Phan⁸, B Lavraud^{9

10}, K A Goodrich^{1

2}, J C Holmes^{1

2}, J E Stawarz^{1

2}, A P Sturner^{1

2}, D M Malaspina¹, M E Usanova¹, K J Trattner¹, R J Strangeway¹¹, C T Russell¹¹, C J Pollock¹², B L Giles¹², M Hesse¹², P-A Lindqvist¹³, J F Drake⁶, M A Shay¹⁴, R Nakamura¹⁵, G T Marklund¹³

Affiliations

¹ Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303, USA.
² Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, Colorado 80303, USA.
³ The Blackett Laboratory, Imperial College, London SW7 2AZ, United Kingdom.
⁴ West Virginia University, Morgantown, West Virginia 26506, USA.
⁵ Southwest Research Institute, San Antonio, Texas 78238-5166, USA.
⁶ University of Maryland, College Park, Maryland 20742, USA.
⁷ University of New Hampshire, Durham, New Hampshire 03824, USA.
⁸ Space Sciences Laboratory, University of California, Berkeley, California 94720, USA.
⁹ Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, 31028 Toulouse, France.
¹⁰ Centre National de la Recherche Scientifique, UMR 5277, Toulouse, France.
¹¹ University of California, Los Angeles, Los Angeles, California 90095, USA.
¹² NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.
¹³ KTH Royal Institute of Technology, SE-11428 Stockholm, Sweden.
¹⁴ University of Delaware, Newark, Delaware 19716, USA.
¹⁵ Space Research Institute, Austrian Academy of Sciences, 8042 Graz, Austria.

PMID: 27419573
DOI: 10.1103/PhysRevLett.117.015001

Abstract

We report observations from the Magnetospheric Multiscale (MMS) satellites of a large guide field magnetic reconnection event. The observations suggest that two of the four MMS spacecraft sampled the electron diffusion region, whereas the other two spacecraft detected the exhaust jet from the event. The guide magnetic field amplitude is approximately 4 times that of the reconnecting field. The event is accompanied by a significant parallel electric field (E_{∥}) that is larger than predicted by simulations. The high-speed (∼300 km/s) crossing of the electron diffusion region limited the data set to one complete electron distribution inside of the electron diffusion region, which shows significant parallel heating. The data suggest that E_{∥} is balanced by a combination of electron inertia and a parallel gradient of the gyrotropic electron pressure.