HR: 1330h
AN: SA22A-0097    [PDF]
TI: Mesoscale and semiglobal scale view of the ionospheric electrodynamics of auroral torches
AU: Amm, O
EM: Olaf.Amm@fmi.fi
AF: Finnish Meteorological Institute, Geophysical Research Division P.O. Box 503, Helsinki, 00101 Finland
AU: * Aksnes, A
EM: Arve.Aksnes@fi.uib.no
AF: University of Bergen, Department of Physics, Bergen, 5007 Norway
AU: Stadsnes, J
EM: Johan.Stadsnes@fi.uib.no
AF: University of Bergen, Department of Physics, Bergen, 5007 Norway
AU: Ostgaard, N
EM: nikost@ssl.berkeley.edu
AF: University of California, Space Sciences Laboratory Addition, Berkeley, CA 94720-7450 United States
AU: Vondrak, R R
EM: Richard.R.Vondrak@nasa.gov
AF: NASA/Goddard Space Flight Center, Code 690, Greenbelt, MD 20771 United States
AU: Germany, G A
EM: germanyg@cspar.uah.edu
AF: University of Alabama, Center for Space Plasma and Aeronomy Research, Huntsville, AL 35899 United States
AU: Lu, G
EM: ganglu@hao.ucar.edu
AF: NCAR, HAO, Boulder, CO 80307-3000 United States
AU: Pulkkinen, A
EM: Antti.Pulkkinen@fmi.fi
AF: Finnish Meteorological Institute, Geophysical Research Division P.O. Box 503, Helsinki, 00101 Finland
AU: Sillanpaa, I
EM: isillanp@pcu.helsinki.fi
AF: Finnish Meteorological Institute, Geophysical Research Division P.O. Box 503, Helsinki, 00101 Finland
AB: Within a substorm recovery phase, a train of omega bands formed in the early morning sector of the auroral oval on June 26, 1998, from ~ 02-04 UT. Some of the omega bands extended far polewards as auroral torches. These phenomena were observed on a semiglobal scale using the UVI and PIXIE instruments on the POLAR satellite, allowing to estimate electron spectra and ionospheric conductance distributions. In addition, semiglobal scale estimates of horizontal currents, field-aligned currents, and Joule heating were calculated using the AMIE procedure. Simultaneously, the omega bands/ torches were observed in Northern Scandinavia by the MIRACLE network, consisting of the IMAGE magnetometer network, the STARE coherent scatter radar, and all-sky cameras. The ground magnetic data were supplemented by the temporary BEAR network, the most extensive and dense magnetometer network set up in Scandinavia as yet. The ground-based data allow to calculate two-dimensional distributions of ionospheric horizontal currents, conductances, and field-aligned currents on a scale of ~ 50 km (mesoscale), using the 2D method of characteristics. In this presentation we concentrate on the analysis of the mesoscale ionospheric electrodynamics of the auroral torches for a few selected, representative timesteps. These results will be embedded in and compared with the semiglobal observations and analysis results. Particularly, we developed a new technique of combining UVI and PIXIE data that allows us to compute the conductances on areas smaller than the original ~ 700 km resolution of PIXIE. We compare the results of this technique with the ones of the 2D method of characteristics.
DE: 2407 Auroral ionosphere (2704)
DE: 2409 Current systems (2708)
DE: 2411 Electric fields (2712)
DE: 2455 Particle precipitation
DE: 2494 Instruments and techniques
SC: SPA - Aeronomy [SA]
MN: 2003 Fall Meeting