HR: 12:10h
AN: SM22A-08    [Abstracts]
TI: Space Technology 5 Multi-point Observations of Field-aligned Currents: Temporal Variability of Meso-Scale Structures
AU: * Le, G
EM: Guan.Le@nasa.gov
AF: NASA Goddard Space Flight Center, Space Weather Laboratory, Code 674, NASA/GSFC, Greenbelt, MD 20771,
AU: Wang, Y
EM: yongli.wang@nasa.gov
AF: UMBC/GEST at Goddard Space Flight Center, Space Weather Laboratory, Code 674, NASA/GSFC, Greenbelt, MD 20771,
AU: Slavin, J A
EM: James.A.Slavin@nasa.gov
AF: NASA Goddard Space Flight Center, Heliophysics Science Division, Code 670, NASA/GSFC, Greenbelt, MD 20771,
AU: Strangeway, R J
EM: strange@igpp.ucla.edu
AF: UCLA, IGPP/UCLA, Los Angeles, CA 90095-1567,
AB: Space Technology 5 (ST5) is a three micro-satellite constellation deployed into a 300 x 4500 km, dawn-dusk, sun-synchronous polar orbit from March 22 to June 21, 2006, for technology validations. In this paper, we present a study of the temporal variability of field-aligned currents using multi-point magnetic field measurements from ST5. The data demonstrate that maso-scale current structures are commonly embedded within large-scale field- aligned current sheets. The meso-scale current structures are very dynamic with highly variable current density and/or polarity in time scales of ~ 10 min. They exhibit large temporal variations during both quiet and disturbed times in such time scales. On the other hand, the data also shown that the time scales for the currents to be relatively stable are ~ 1 min for meso-scale currents and ~ 10 min for large scale current sheets. These temporal features are obviously associated with dynamic variations of their particle carriers (mainly electrons) as they respond to the variations of the parallel electric field in auroral acceleration region. The characteristic time scales for the temporal variability of meso-scale field-aligned currents are found to be consistent with those of auroral parallel electric field.
DE: 2407 Auroral ionosphere (2704)
DE: 2409 Current systems (2721)
DE: 2704 Auroral phenomena (2407)
DE: 2721 Field-aligned currents and current systems (2409)
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting