Articles | Volume 24, issue 10
20 Oct 2006
 | 20 Oct 2006

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

K. Nykyri, A. Otto, B. Lavraud, C. Mouikis, L. M. Kistler, A. Balogh, and H. Rème

Abstract. 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 bz-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 RE and a wave vector with a significant z-component.