In situ spacecraft observations of a structured electron diffusion region during magnetopause reconnection

Giulia Cozzani; A Retinò; F Califano; A Alexandrova; O Le Contel; Y Khotyaintsev; A Vaivads; H S Fu; F Catapano; H Breuillard; N Ahmadi; P-A Lindqvist; R E Ergun; R B Torbert; B L Giles; C T Russell; R Nakamura; S Fuselier; B H Mauk; T Moore; J L Burch

doi:10.1103/PhysRevE.99.043204

In situ spacecraft observations of a structured electron diffusion region during magnetopause reconnection

Phys Rev E. 2019 Apr;99(4-1):043204. doi: 10.1103/PhysRevE.99.043204.

Authors

Giulia Cozzani^{1

2}, A Retinò¹, F Califano², A Alexandrova¹, O Le Contel¹, Y Khotyaintsev³, A Vaivads³, H S Fu⁴, F Catapano^{1

5}, H Breuillard^{1

6}, N Ahmadi⁷, P-A Lindqvist⁸, R E Ergun⁷, R B Torbert⁹, B L Giles¹⁰, C T Russell¹¹, R Nakamura¹², S Fuselier^{13

14}, B H Mauk¹⁵, T Moore¹⁰, J L Burch¹³

Affiliations

¹ Laboratoire de Physique des Plasmas, CNRS/Ecole Polytechnique/Sorbonne Université, Université Paris Sud, Observatoire de Paris, 91128 Palaiseau, France.
² Dipartimento di Fisica "E. Fermi", Università di Pisa, I-56127 Pisa, Italy.
³ Swedish Institute of Space Physics, SE-75121 Uppsala, Sweden.
⁴ School of Space and Environment, Beihang University, Beijing, 100083, P.R. China.
⁵ Dipartimento di Fisica, Università della Calabria, I-87036, Arcavacata di Rende (CS), Italy.
⁶ Laboratoire de Physique et Chimie de l'Environnement et de l'Espace, CNRS-Université d'Orléans, UMR 7328, 45071 Orléans, France.
⁷ Laboratory of Atmospheric and Space Physics, University of Colorado Boulder, Boulder, Colorado 80309, USA.
⁸ KTH Royal Institute of Technology, SE-10044, Stockholm, Sweden.
⁹ Space Science Center, University of New Hampshire, Durham, New Hampshire 03824, USA.
¹⁰ NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA.
¹¹ Department of Earth and Space Sciences, University of California, Los Angeles, California 90095, USA.
¹² Space Research Institute, Austrian Academy of Sciences, 8042 Graz, Austria.
¹³ Southwest Research Institute, San Antonio, Texas 78238, USA.
¹⁴ University of Texas at San Antonio, San Antonio, Texas 78238, USA.
¹⁵ The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland 20723, USA.

PMID: 31108651
DOI: 10.1103/PhysRevE.99.043204

Abstract

The electron diffusion region (EDR) is the region where magnetic reconnection is initiated and electrons are energized. Because of experimental difficulties, the structure of the EDR is still poorly understood. A key question is whether the EDR has a homogeneous or patchy structure. Here we report Magnetospheric Multiscale (MMS) spacecraft observations providing evidence of inhomogeneous current densities and energy conversion over a few electron inertial lengths within an EDR at the terrestrial magnetopause, suggesting that the EDR can be rather structured. These inhomogenenities are revealed through multipoint measurements because the spacecraft separation is comparable to a few electron inertial lengths, allowing the entire MMS tetrahedron to be within the EDR most of the time. These observations are consistent with recent high-resolution and low-noise kinetic simulations.