Kelvin-Helmholtz waves at the Earth's magnetopause: Multiscale development and associated reconnection

摘要: [1] We examine traversals on 20 November 2001 of the equatorial magnetopause boundary layer simultaneously at ∼1500 magnetic local time (MLT) by Geotail spacecraft and ∼1900 MLT Cluster spacecraft, which detected rolled-up MHD-scale vortices generated Kelvin-Helmholtz instability (KHI) under prolonged northward interplanetary field conditions. Our purpose is to address excitation process KHI, ion-scale structures vortices, formation mechanism low-latitude (LLBL). The observed KH wavelength (>4 × 104 km) considerably longer than predicted linear theory from thickness (∼1000 dayside velocity shear layer. analyses suggest that KHI facilitated combined effects LLBL presumably through high-latitude reconnection compressional magnetosheath fluctuations dayside, breakup and/or coalescence are beginning around 1900 MLT. Current layers a few times ion inertia length ∼100 km ∼60° existed trailing edges vortices. Identified in one such current sheet were signatures reconnection: Alfvenic outflow jet within bifurcated sheet, nonzero component normal field-aligned beam accelerated electrons. Because its incipient nature, however, this unlikely lead dusk-flank LLBL. It thus inferred flank resulted other mechanisms, namely, diffusion remote unidentified Cluster.