HR: 0800h
AN: SM31A-0386    [Abstracts]
TI: Substorm onset location and the Harang discontinuity
AU: Springborn, J
EM: purplewhoppie@yahoo.com
AF: Institute of Geophysics and Planetary Physics, UCLA, PO Box 951567 3845 Slichter Hall, Los Angeles, CA 90095-1567 United States
AU: Weygand, J M
EM: jweygand@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics, UCLA, PO Box 951567 3845 Slichter Hall, Los Angeles, CA 90095-1567 United States
AU: Amm, O
EM: Olaf.Amm@fmi.fi
AF: Finnish Meteorological Institute, Space Physics Program, P.O. Box 503, Helsinki, 00101 Finland
AU: * McPherron, R L
EM: rmcpherron@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics, UCLA, PO Box 951567 3845 Slichter Hall, Los Angeles, CA 90095-1567 United States
AU: Kauristie, K
EM: Kirsti.Kauristie@fmi.fi
AF: Finnish Meteorological Institute, Space Physics Program, P.O. Box 503, Helsinki, 00101 Finland
AU: Frey, H
EM: hfrey@ssl.berkeley.edu
AF: Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley, CA 94720-7450 United States
AB: In this study we investigate the relation of auroral substorm onset to the Harang discontinuity. With a database of over 3300 onsets determined from auroral images we will statistically examine the MLat and MLT location of the onset with respect to the location of the Harang discontinuity as determined with data from the IMAGE magnetometer network. We define the location of the Harang discontinuity as the transition from eastward to westward currents at the latitude of the main auroral electrojet flow. This work will address the long standing question of whether the substorm onset is initiated equatorward of the Harang discontinuity within the eastward electrojet region as proposed by Baumjohann [1983].
DE: 2721 Field-aligned currents and current systems (2409)
DE: 2731 Magnetosphere: outer
DE: 2776 Polar cap phenomena
DE: 2790 Substorms
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005