HR: 1340h
AN: SM23A-0486    [Abstracts]
TI: Auroral Undulations in the Afternoon/Dusk Sector Observed with the IMAGE FUV/Wideband Imaging Camera and Their Magnetic Connection to Plasmaspheric Plumes
AU: * Lewis, W S
EM: wlewis@swri.edu
AF: Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228 United States
AU: Burch, J L
EM: jburch@swri.edu
AF: Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228 United States
AU: Goldstein, J
EM: jgoldstein@swri.edu
AF: Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228 United States
AU: Mende, S B
EM: mende@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, Berkeley, Berkeley, CA 94720 United States
AU: Frey, H U
EM: hfrey@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, Berkeley, Berkeley, CA 94720 United States
AU: Immel, T J
EM: immel@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, Berkeley, Berkeley, CA 94720 United States
AU: Thomsen, M F
EM: mthomsen@lanl.gov
AF: Space and Atmospheric Sciences (NIS-1), Los Alamos National Laboratory, Los Alamos, NM 87545 United States
AU: Sandel, B R
EM: sandel@arizona.edu
AF: Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 United States
AB: On February 6, 2002 the IMAGE FUV/Wideband Imaging Camera (WIC) detected a periodic series of tongue-like emission features that extended equatorward from the main auroral oval in the afternoon/dusk sector. Although clearly discernible in the electron aurora, these features cannot be distinguished from background in simultaneous images of the proton aurora. The emission tongues were observed during the recovery phase of a moderate magnetic storm and occurred during a substorm expansion phase. Their wavelength, amplitude, and westward velocity are consistent with those reported for giant undulations observed at the equatorward edge of the diffuse aurora. However, the features seen on February 6 are embedded within a broader band of diffuse auroral emissions and in two instances are observed to brighten in conjunction with brief, localized intensifications along the portion of the oval to which they are connected. The emission tongues map to a well-developed plasmaspheric drainage plume, seen in geosynchronous plasma data as well as in near-simultaneous data from the IMAGE Extreme Ultraviolet (EUV) imager. We discuss this event in the context of previous work on undulations at the equatorward edge of the aurora and consider its implications for the various mechanisms that have been proposed to account for such structures.
DE: 2407 Auroral ionosphere (2704)
DE: 2704 Auroral phenomena (2407)
DE: 2736 Magnetosphere/ionosphere interactions
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting