HR: 1400h
AN: SM33A-04    [Abstracts]
TI: The Effects of IMF and Convection on Thermal Ion Outflow in Magnetosphere-Ionosphere Coupling
AU: * Yau, A W
EM: yau@phys.ucalgary.ca
AF: University of Calgary, Department of Physics and Astronomy 2500 University Dr NW, Calgary, AB T2N1N4, Canada
AU: Howarth, A
EM: howarth@phys.ucalgary.ca
AF: University of Calgary, Department of Physics and Astronomy 2500 University Dr NW, Calgary, AB T2N1N4, Canada
AB: We study the influence of the IMF and convection electric field on the rate and destination of thermal (low-energy) ion outflows, and its resulting effects on magnetosphere-ionosphere coupling, using single-particle trajectory simulations and ion velocity distribution measurements on Akebono in conjunction with IMF and ionospheric convection data. We find that the ions preferentially feed the dusk sector of the plasma sheet when the IMF is duskward (By > 0), and are more evenly distributed in the plasma sheet when the IMF is dawnward. The flow of oxygen ions originating from the noon or dusk sectors of the polar cap has a higher probability of reaching the magnetosphere and beyond compared with that from the dawn or midnight sectors, due to the increased centrifugal acceleration associated with the larger magnetic field curvature near noon and the increased convection electric field in the dusk sector. The flow is enhanced and confined to lower L-shells at times of strongly southward IMF, compared with that at times of northward IMF. The outflow rate to both the plasma sheet and the magnetotail correlates strongly with the ion temperature. As a result, the IMF and the convection electric fields affect both the overall magnitude and the detailed distribution of mass transfer from the ionosphere to the magnetosphere in magnetosphere-ionosphere coupling.
DE: 2736 Magnetosphere/ionosphere interactions (2431)
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Joint Assembly