Magnetic reconnection and modification of the Hall physics due to cold ions at the magnetopause

M. André , W. Li , S. Toledo-Redondo , Yu. V. Khotyaintsev , A. Vaivads , D. B. Graham , C. Norgren , J. Burch , P. -A. Lindqvist , G. Marklund , R. Ergun , R. Torbert , W. Magnes , C. T. Russell , B. Giles , T. E. Moore , M. O. Chandler , C. Pollock , D. T. Young , L. A. Avanov , J. C. Dorelli , D. J. Gershman , W. R. Paterson , B. Lavraud (1) , Y. Saito

1 IRAP - Institut de recherche en astrophysique et planétologie

Observations by the four Magnetospheric Multiscale spacecraft are used to investigate the Hall physics of a magnetopause magnetic reconnection separatrix layer. Inside this layer of currents and strong normal electric fields, cold (eV) ions of ionospheric origin can remain frozen-in together with the electrons. The cold ions reduce the Hall current. Using a generalized Ohm's law, the electric field is balanced by the sum of the terms corresponding to the Hall current, the v × B drifting cold ions, and the divergence of the electron pressure tensor. A mixture of hot and cold ions is common at the subsolar magnetopause. A mixture of length scales caused by a mixture of ion temperatures has significant effects on the Hall physics of magnetic reconnection.

Keywords: magnetic reconnection; magnetopause; electric fields; Hall current

Domains: Sciences of the Universe [physics]

M. André, W. Li, S. Toledo-Redondo, Yu. V. Khotyaintsev, A. Vaivads, et al.. Magnetic reconnection and modification of the Hall physics due to cold ions at the magnetopause. Geophysical Research Letters, 2016, 43, pp.6705-6712. ⟨10.1002/2016GL069665⟩. ⟨insu-03669467⟩