HR: 1340h
AN: SM13A-0318    [Abstracts]
TI: Improved Representation of Magnetospheric Electric Potential Structure on a Polar-Capped Ionosphere
AU: * Schulz, M
EM: mike.schulz@lmco.com
AF: Lockheed Martin Advanced Technology Center, Dept ADCS, Bldg 255, 2351 Hanover Street, Palo Alto, CA 94304 United States
AB: In some simple models of magnetospheric electrodynamics [e.g., Volland, 1975], the normal component of the convection electric field E is discontinuous across the boundary between closed and open magnetic field lines. The requisite discontinuity in E is achieved by making the electrostatic scalar potential proportional to a positive power (typically 1 or 2) of L on closed field lines and to a negative power (typically -1/2) of L on open (i.e., polar-cap) field lines. It may be advantageous to construct more realistic (and thus more complicated) magnetospheric and ionospheric electric-field models from superpositions of (not necessarily orthogonal) functions having this same analytical property (i.e., discontinuity of derivative at L = L*, the boundary surface between closed and open magnetic field lines). For an ionosphere with realistically situated polar caps, such analytical functions would reasonably involve powers of the cosine function of a magnetic quasi-latitude and sines or cosines of integer multiples of a quasi-MLT variable, both coordinates being defined in terms of a coordinate-potential function held constant (at values equal in magnitude but opposite in sign) on the boundaries between closed and open magnetic field lines. Quasi-latitudes in this construction are contours of constant coordinate potential, and quasi-MLT contours are "streamline" trajectories orthogonal to the coordinate equipotentials.
DE: 2411 Electric fields (2712)
DE: 2447 Modeling and forecasting
DE: 2712 Electric fields (2411)
DE: 2736 Magnetosphere/ionosphere interactions (2431)
DE: 2776 Polar cap phenomena
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005