Cluster observations of reconnection due to the Kelvin-Helmholtz instability at the dawnside magnetospheric flank

K. Nykyri (1) , A. Otto (2) , B. Lavraud (3) , C. Mouikis (4) , L. M. Kistler (4) , A. Balogh (1) , H. Rème (5)

1 Blackett Laboratory
2 Geophysical Institute
3 LANL - Los Alamos National Laboratory
4 UNH - University of New Hampshire
5 CESR - Centre d'étude spatiale des rayonnements

On 3 July 2001, the four Cluster satellites traversed along the dawnside magnetospheric flank and observed large variations in all plasma parameters. The estimated magnetopause boundary normals were oscillating in the z-direction and the normal component of the magnetic field showed systematic 2–3 min bipolar variations for 1 h when the IMF had a small positive b_z-component and a Parker-spiral orientation in the x,y-plane. Brief 33 s intervals with excellent deHoffman Teller frames were observed satisfying the Walén relation. Detailed comparisons with 2-D MHD simulations indicate that Cluster encountered rotational discontinuities generated by Kelvin-Helmholtz instability. We estimate a wave length of 6 R_E and a wave vector with a significant z-component.

Domaines: Océan, Atmosphère; Sciences de la Terre

K. Nykyri, A. Otto, B. Lavraud, C. Mouikis, L. M. Kistler, et al.. Cluster observations of reconnection due to the Kelvin-Helmholtz instability at the dawnside magnetospheric flank. Annales Geophysicae, 2006, 24 (10), pp.2619-2643. ⟨hal-00330090⟩