HR: 09:15h
AN: SM51C-06    [Abstracts]
TI: Comparison of local energy transfer estimates from Cluster with global MHD simulations
AU: * Rosenqvist, L
EM: lr@irfu.se
AF: Swedish Institute of Space Physics, Lagerhyddsvagen 1, Uppsala, 75121, Sweden
AU: Opgenoorth, H
EM: hopgenoorth@rssd.esa.int
AF: Solar System Mission Division, ESA/ESTEC, Noordwijk, Netherlands
AB: We have used several magnetopause crossings by the multi-spacecraft mission Cluster to make observational estimates of the local energy transfer across the magnetopause. During one occasion we could identify a load region on the dayside high-latitude magnetopause, where the energy was found to be transferred from the magnetic field to the particles as a probable consequence of the reconnection process during southward IMF. During another crossing further towards the dawn flank of the magnetosphere we could identify a generator region, where solar wind kinetic energy was transferred to the magnetic field as a result of magnetic stresses along the magnetopause during dominantly duskward IMF. These results from real spacecraft crossings have at the same locations been compared to the BATS-R-US global MHD simulation results, using the actual ACE solar wind plasma and magnetic field measurements from the individual events as model input. The local characteristics of the global model results correctly predict the regions crossed by Cluster during the two different cases as a load and a generator region, correspondingly. Furthermore, the magnitude of the energy transfer across the magnetopause as deduced from Cluster and the model are in reasonable agreement. These results may help to validate the use of global MHD simulations to estimate the total energy input to the magnetosphere, which is of considerable importance for Space Weather considerations. Also, it appears that any local Cluster observations at the magnetopause can be used to scale the MHD model results to obtain better global estimates.
DE: 2723 Magnetic reconnection (7526, 7835)
DE: 2724 Magnetopause and boundary layers
DE: 2740 Magnetospheric configuration and dynamics
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Joint Assembly