HR: 09:00h
AN: SA41A-04    [Abstracts]
TI: The quiet and disturbed sub-auroral electric field as observed from DMSP
AU: * Talaat, E R
EM: elsayed.talaat@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, United States
AU: Sotirelis, T S
EM: tom.sotirelis@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, United States
AU: Hairston, M R
EM: hairston@utdallas.edu
AF: University of Texas at Dallas, W. B. Hanson Center for Space Sciences, Richardson, TX 75083, United States
AU: Brandt, P C
EM: pontus.brandt@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, United States
AU: Zheng, Y
EM: yihua.zheng@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, United States
AU: Ohtani, S
EM: shin.ohtani@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, United States
AU: Wing, S
EM: simon.wing@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, United States
AU: Higuchi, T
EM: higuchi@ism.ac.jp
AF: Institution of Statistical Mathematics, Department of Statistical Modeling, Tokyo, Japan
AU: Ueno, G
EM: gen@ism.ac.jp
AF: Institution of Statistical Mathematics, Department of Statistical Modeling, Tokyo, Japan
AB: Though the high and low latitude electric field has been studied and modeled extensively (e.g., Rich and Hairston, 1994, Weimer, 1995, Ruohoniemi and Greenwald, 1996, Richmond, 1995; Fejer, 1997) there has been relatively little attention to the sub-auroral region except for studies at certain longitudes (e.g., Foster and Vo, 2002). In this paper we present preliminary analyses of the quiet and disturbed sub-auroral electric field environment. The variability that is seen in mid-latitudes may partially be the result of the same factors at high latitudes. It has been shown that the configuration and strength of the high latitude electric field is dependent on the inter-planetary magnetic field orientation (e.g., Ruohoniemi and Greenwald, 1996) and geomagnetic activity. The sub-auroral electric field will also have a strong IMF and geomagnetic component, but is also expected to have significant longitudinal, seasonal, and solar cycle variation, as the mid-latitude conductivity is highly dependent on solar illumination. We use the long-term (18 years) electric field measurement dataset provided by the suite of DMSP ion drift meters (the measured ion drifts are related to the electric fields by v=(ExB)/(B*B) ). By definition, a major component of correctly identifying sub-auroral electric fields is to correctly specify the aurora boundary, as the behavior and magnitude of these fields will be drastically different away from the high-conductance auroral oval. For this analysis, we also use coincident particle flux measurements from the DMSP SSJ4 monitors. We examine the climatogical and storm-time sub-auroral electric field as a function of invariant latitude as well as gridded relative to auroral boundary. We also discuss the relationship between the sub-auroral electric field and the mid- latitude trough and region 2 field-aligned currents.
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2435 Ionospheric disturbances
DE: 2463 Plasma convection (2760)
DE: 2712 Electric fields (2411)
SC: SPA-Aeronomy [SA]
MN: 2007 Joint Assembly