HR: 0800h
AN: SA51A-0242    [Abstracts]
TI: Satellite based determination of Ionospheric Conductances due to solar illumination and particle precpitation
AU: Burke, W
AF: Air Force Research Lab, VSBXP 29 Randolf Road, Hanscom AFB, MA 01731, United States
AU: Burke, W
AF: Boston College, 402 St. Clement's Hall 140 Commonwealth Ave, Chestnut Hill, MA 02467, United States
AU: * Wilson, G R
EM: gordon.wilson.ctr@hanscom.af.mil
AF: Boston College, 402 St. Clement's Hall 140 Commonwealth Ave, Chestnut Hill, MA 02467, United States
AB: The Pedersen conductance is an important parameter that determines the intensity of currents coupling the ionosphere and the magnetosphere and the rate of electromagnetic energy exchange between the two. Short of running a full ionosphere/thermosphere model, studies of ionosphere/magnetosphere coupling are forced to rely on various sets of emperical or parameterized theoretical results to determine local or global conductance. Under steady state conditions Ampere's and Ohm's laws can be combined to obtain the relationship between magnetic perturbations and electric fields measured at satellite altitudes in regions of field-aligned currents. In intervals where E and δ B are highly correlated the height integrated Pedersen conductivity can be written as Σ_P = (1/μ_o) Δ δ B_Z/ Δ E_Y, and be determined directly from in situ measurements. We use this approach with magnetometer and driftmeter data from two DMSP satellites (F16 and F17) to determine Pedersen conductances under quiet to mildly distrubed conditions, in regions close to the terminator where solar illumination and particle (ion and electron) precipitation play competing roles in determing ionospheric conductivities. Results from this study are compared with commonly used expressions for conductances ( Robinson and Vondrak, 1984; Robinson et al., 1987) and results of numerical simulations.
DE: 2704 Auroral phenomena (2407)
DE: 2721 Field-aligned currents and current systems (2409)
DE: 2736 Magnetosphere/ionosphere interactions (2431)
SC: SPA-Aeronomy [SA]
MN: 2007 Fall Meeting