Abstract
Dependence of flux transfer events on solar wind conditions from 3 years of Cluster observations
Space Science and Applications, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
Space Science and Applications, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
Space Science and Applications, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
Space Science and Applications, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
Mullard Space Science Laboratory, University College London, London, UK
Space Science and Applications, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, California, USA
Space Science Center, University of New Hampshire, Durham, New Hampshire, USA
Department of Earth and Planetary Sciences, Kyushu University, Fukuoka, Japan
Key Laboratory of Space Weather, Center for Space Science and Applied Research, Beijing, China
We investigate the dependence of Cluster high-latitude magnetopause and low-latitude flank flux transfer events (FTEs) on solar wind conditions using measurements from Cluster FGM and CIS and ACE MFI and SWEPAM between February 2001 and June 2003. We find that there are strong dependences of Cluster FTE occurrence on the IMF B xgsm , B ygsm , and B zgsm components but not on the IMF magnitude. There are strong dependences of Cluster FTE occurrence on the IMF clock, tilt, spiral, and cone angles. However, some patterns are significantly different from previous results. The solar wind density, speed, Beta, V x B z , dynamic pressure, and magnetosonic Mach number have different degrees of control on FTE occurrence. FTE separation time is found to be clearly controlled by IMF B ygsm , B zgsm , and magnitude, and the IMF clock, tilt, spiral, and cone angles, and weakly controlled by the solar wind V x B z and magnetosonic Mach number. There is no obvious control of it by other IMF and solar wind parameters. FTE peak-peak magnitude is found to be controlled by IMF B ygsm , B zgsm , and magnitude and by the solar wind density and dynamic pressure but not by other IMF and solar wind parameters. The FTE dawn-dusk asymmetry is not likely caused by the Parker spiral IMF. Some FTE statistical patterns are strongly dependent on FTE locations. Finally, we see ∼4% of the FTEs corresponding to a single change in IMF B zgsm from positive to negative, ∼4% corresponding to a single change from negative to positive, and ∼43% corresponding to multiple changes in the sign of IMF B zgsm , all within the 10-min interval preceding the FTEs. There is still no evidence for a direct correlation between IMF B zgsm changing sign and FTEs.
Received 28 July 2005; accepted 23 January 2006; published 29 April 2006.
Citation: (2006), Dependence of flux transfer events on solar wind conditions from 3 years of Cluster observations, J. Geophys. Res., 111, A04224, doi:10.1029/2005JA011342.
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