HR: 1340h
AN: SM23A-1188    [Abstracts]
TI: Time Evolution of the Substorm Current Wedge from Ground and Space-based Magnetic Fields
AU: * Connors, M
EM: martinc@athabascau.ca
AF: Athabasca University, 1 University Drive, Athabasca, AB T9S 3A3, Canada
AU: Russell, C T
EM: ctrussel@igpp.ucla.edu
AF: IGPP, UCLA, Box 951567, Los Angeles, CA 90095, United States
AU: Donovan, E
EM: edonovan@ucalgary.ca
AF: Department of Physics and Astronomy, University of Calgary, Calgary, AB T2N 1N4, Canada
AU: Angelopoulos, V
EM: vassilis@ucla.edu
AF: IGPP, UCLA, Box 951567, Los Angeles, CA 90095, United States
AU: Voronkov, I
EM: igor@phys.ucalgary.ca
AF: Athabasca University, 1 University Drive, Athabasca, AB T9S 3A3, Canada
AU: Mende, S B
EM: mende@ssl.berkeley.edu
AF: University of California, Berkeley, Space Sciences Laboratory, 7 Gauss Way, Berkeley, CA 94720-7450, United States
AU: Glassmeier, K
EM: kh.glassmeier@tu-bs.de
AF: TU Braunschweig, Institute of Geophysics Mendelssohnstr 3, Braunschweig, 38106, Germany
AU: Hayashi, K
EM: QYI05527@nifty.ne.jp
AF: University of Tokyo, Department of Earth and Planetary Science, Tokyo, 113-0033, Japan
AU: Spanswick, E
EM: emma@phys.ucalgary.ca
AF: Department of Physics and Astronomy, University of Calgary, Calgary, AB T2N 1N4, Canada
AU: Jackel, B
EM: bjackel@ucalgary.ca
AF: Department of Physics and Astronomy, University of Calgary, Calgary, AB T2N 1N4, Canada
AU: Frey, H
EM: hfrey@ssl.berkeley.edu
AF: University of California, Berkeley, Space Sciences Laboratory, 7 Gauss Way, Berkeley, CA 94720-7450, United States
AU: McFadden, J P
EM: mcfadden@ssl.berkeley.edu
AF: University of California, Berkeley, Space Sciences Laboratory, 7 Gauss Way, Berkeley, CA 94720-7450, United States
AB: Over the past several years, intensive efforts have resulted in a significant improvement in the ground instrumentation for auroral studies in North America. A major part of this is due to the THEMIS ground program, both in the U.S. and in Canada. The THEMIS Ground-Based Observatory network has fielded 10 additional magnetometers in Canada and Alaska. Further THEMIS magnetometers are part of the GEONS outreach effort, found in the continental U.S. and Alaska. Athabasca University initiatives and collaborations have made yet further magnetometer data available, most notably from the new AUTUMN network of instruments in central Alberta, and others in Quebec. Several stations of the University of Tokyo STEP network remain operational, and some have been upgraded. There is finally a dense enough set of magnetic data that techniques based on forward modeling, and most relevant to the opportunity afforded by THEMIS, Automated Regional Modeling (ARM), can be reliably used. These techniques specify where net field-aligned current (FAC) and ionospheric electric current flow are located. In some cases the Pedersen system can also be included based on data. Even when it is not, it can be considered collocated with electrojet locations given by ARM. The extension into space of the FAC (net or Pedersen) allows comparison with the perturbations observed at THEMIS. We present results from an event on March 13, 2007, during which THEMIS in its early orbital configuration was magnetically conjugate to central North America, clear weather prevailed, and a substorm took place whose perturbations were ideally suited for inversion using ARM. At about 5 UT, activations were detected from the ground with magnetic perturbations also detected from THEMIS. The ground perturbations are well represented by a three-dimensional substorm current wedge (SCW) system, and perturbations in space indicate radial propagation at a time when the electrojet expanded poleward. Little longitudinal propagation of the SCW is suggested by the ground data.
DE: 2704 Auroral phenomena (2407)
DE: 2721 Field-aligned currents and current systems (2409)
DE: 2753 Numerical modeling
DE: 2790 Substorms
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting