SM14A-03
The Role of Kelvin-Helmholtz Waves in Magnetosphere-Ionosphere Coupling
Monday, 14 December 2015: 16:28
2016 (Moscone West)
Kyoung-Joo Hwang1, David G Sibeck2, Sun-Hee Lee1, Yukitoshi Nishimura3, James M Weygand4, Eric Donovan5 and Emma Spanswick5, (1)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (2)NASA/GSFC, Greenbelt, MD, United States, (3)University of California Los Angeles, Department of Atmospheric and Ocean Science, Los Angeles, CA, United States, (4)University of California Los Angeles, Los Angeles, CA, United States, (5)University of Calgary, Calgary, AB, Canada
Abstract:
We inspect simultaneous multipoint spacecraft and ground-based measurements to determine the role of Kelvin-Helmholtz waves at the Earth’s magnetopause and the low-latitude boundary layer (LLBL) in magnetosphere-ionosphere coupling. Nonlinear Kelvin-Helmholtz waves develop into flow vortices that twist or shear flux tube magnetic fields, thereby generating localized field-aligned currents. Kelvin-Helmholtz vortices on the dusk (dawn) flanks of the magnetosphere generate clockwise (counter-clockwise) rotations and upward (downward) field-aligned currents inside the flux tubes. We present in-situ Cluster and THEMIS spacecraft observations of Kelvin-Helmholtz vortices and associated physical processes at the magnetopause that map to the poleward edge of the auroral regions where they can be observed by low-altitude FAST and ground-based instruments (magnetograms, riometer data, and all sky images), thereby linking magnetopause boundary fluctuations to transient ionospheric phenomena.
