HR: 0800h
AN: SM51A-0349    [Abstracts]
TI: Self-consistent Solution for the Electrostatic Potential Distribution Along Auroral Magnetic Field Lines
AU: * Bostrom, R
EM: rolf.g.bostrom@telia.com
AF: Rolf Bostrom, Swedish Institute of Space Physics Box 537, Uppsala, SE-75121 Sweden
AB: The distribution of the electrostatic potential along current-carrying auroral magnetic flux tubes is studied analytically, assuming Maxwellian magnetospheric and ionospheric particle sources. Although the current gives the total potential drop from simple orbit theory (Knight's current-voltage relation based on collision-free particle motion conserving energy and momentum), the determination of the potential distribution and electric field requires detailed considerations of (1) particle accessibility, (2) mapping of the source particle distribution functions, and (3) the necessary quasi-neutrality everywhere along the magnetic field lines. In general, a self-consistent solution can only be found if a potential step (electrostatic double layer) is allowed, accounting for a sizable fraction of the total potential drop. For typical parameters this occurs at an altitude of around 1 Re, the potential is nearly constant below the potential step, drops by hundreds of volts or a few kilovolts at the step, and then asymptotically falls of in proportion to the magnetic field intensity.
DE: 2704 Auroral phenomena (2407)
DE: 2712 Electric fields (2411)
DE: 2716 Energetic particles, precipitating
DE: 2736 Magnetosphere/ionosphere interactions
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting