HR: 1330h
AN: SM42B-0606    [PDF]
TI: The theta aurora and ionospheric flow convection: Polar ultraviolet imager and SuperDARN radar observations
AU: * Liou, K
EM: kan.liou@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 United States
AU: Ruohoniemi, J M
EM: mike.ruohoniemi@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 United States
AU: Newell, P T
EM: partick.newell@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 United States
AU: Meng, C I
EM: ching.meng@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 United States
AB: We report results from a case study of the theta aurora that occurred during a magnetic cloud event on November 8, 2000. The interplanetary magnetic field (IMF) was strongly northward for more than 12 hours, while the y-component of IMF changed signs several times. Auroral images from the Ultraviolet Imager on board the Polar satellite show clear instances of theta auroras during the prolonged northward IMF period. This event provides a good opportunity for testing current models of theta aurora generation and evolution. We examine in situ particle data from the DMSP satellites to find magnetospheric source regions responsible for the theta auroras. We also examine ionospheric plasma flow convection data from the SuperDARN radar network to study relationships between the ionospheric plasma flow pattern and the location of the theta auroras. Our results clearly indicate that the theta aurora bar, at least on nightside, was located in a region of anti-sunward convecting flow. This is not consistent with the current view that theta auroras reside in regions of closed field lines and hence in regions of sunward convecting flow. Implication of the new findings will be discussed.
DE: 2704 Auroral phenomena (2407)
DE: 2760 Plasma convection
DE: 2776 Polar cap phenomena
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting