MMS observations of large guide field symmetric reconnection between colliding reconnection jets at the center of a magnetic flux rope at the magnetopause

M. Øieroset , T. D. Phan , C. Haggerty , M. A. Shay , J. P. Eastwood , D. J. Gershman , J. F. Drake , M. Fujimoto , R. E. Ergun , F. S. Mozer , M. Oka , R. B. Torbert , J. L. Burch , S. Wang , L. J. Chen , M. Swisdak , C. Pollock , J. C. Dorelli , S. A. Fuselier , B. Lavraud (1, 2) , B. L. Giles , T. E. Moore , Y. Saito , L. A. Avanov , W. Paterson , R. J. Strangeway , C. T. Russell , Y. Khotyaintsev , P. A. Lindqvist , K. Malakit

1 IRAP - Institut de recherche en astrophysique et planétologie
2 CNRS - Centre National de la Recherche Scientifique

We report evidence for reconnection between colliding reconnection jets in a compressed current sheet at the center of a magnetic flux rope at Earth's magnetopause. The reconnection involved nearly symmetric inflow boundary conditions with a strong guide field of two. The thin (2.5 ion-skin depth (d_i) width) current sheet (at ~12 d_i downstream of the X line) was well resolved by MMS, which revealed large asymmetries in plasma and field structures in the exhaust. Ion perpendicular heating, electron parallel heating, and density compression occurred on one side of the exhaust, while ion parallel heating and density depression were shifted to the other side. The normal electric field and double out-of-plane (bifurcated) currents spanned almost the entire exhaust. These observations are in good agreement with a kinetic simulation for similar boundary conditions, demonstrating in new detail that the structure of large guide field symmetric reconnection is distinctly different from antiparallel reconnection.

Mots clés: magnetic reconnection; particle acceleration; magnetopause; flux rope; magnetospheric multiscale

Domaines: Planète et Univers [physics]

M. Øieroset, T. D. Phan, C. Haggerty, M. A. Shay, J. P. Eastwood, et al.. MMS observations of large guide field symmetric reconnection between colliding reconnection jets at the center of a magnetic flux rope at the magnetopause. Geophysical Research Letters, 2016, 43, pp.5536-5544. ⟨10.1002/2016GL069166⟩. ⟨insu-03669494⟩