Mass Loading the Earth's Dayside Magnetopause Boundary Layer and Its Effect on Magnetic Reconnection

S. Fuselier , K J Trattner , S. Petrinec (1) , M H Denton , S. Toledo-Redondo (2) , M. André (3) , Nicolas Aunai (4) , C R Chappell , A Glocer , S. Haaland (5) , M. Hesse (6) , L. Kistler (7) , B. Lavraud (8) , W. Li (9) , T. Moore (6) , D Graham , L Alm , P Tenfjord , J Dargent , S K Vines , K Nykyri , J L Burch , R J Strangeway

1 ATC - Lockheed Martin Advanced Technology Center
2 ESA - Agence Spatiale Européenne = European Space Agency
3 IRF - Swedish Institute of Space Physics [Uppsala / Kiruna]
4 LPP - Laboratoire de Physique des Plasmas
5 MPE - Max-Planck-Institut für Extraterrestrische Physik
6 GSFC - NASA Goddard Space Flight Center
7 EOS Space Science Center [Durham]
8 IRAP - Institut de recherche en astrophysique et planétologie
9 CFD Lab [Montréal]

When the interplanetary magnetic field is northward for a period of time, O + from the high-latitude ionosphere escapes along reconnected magnetic field lines into the dayside magnetopause boundary layer. Dual-lobe reconnection closes these field lines, which traps O + and mass loads the boundary layer. This O + is an additional source of magnetospheric plasma that interacts with magnetosheath plasma through magnetic reconnection. This mass loading and interaction is illustrated through analysis of a magnetopause crossing by the Magnetospheric Multiscale spacecraft. While in the O +-rich boundary layer, the interplanetary magnetic field turns southward. As the Magnetospheric Multiscale spacecraft cross the high-shear magnetopause, reconnection signatures are observed. While the reconnection rate is likely reduced by the mass loading, reconnection is not suppressed at the magnetopause. The high-latitude dayside ionosphere is therefore a source of magnetospheric ions that contributes often to transient reduction in the reconnection rate at the dayside magnetopause.

Domaines: Géophysique [physics.geo-ph]

S. Fuselier, K J Trattner, S. Petrinec, M H Denton, S. Toledo-Redondo, et al.. Mass Loading the Earth's Dayside Magnetopause Boundary Layer and Its Effect on Magnetic Reconnection. Geophysical Research Letters, 2019, 46 (12), pp.6204-6213. ⟨10.1029/2019GL082384⟩. ⟨hal-02372816⟩