Ionospheric convection observations following the solar flare of 20 January 2005 and during the geomagnetic storm of 21 January 2005

HR: 1340h
AN: SH23A-0331 [Abstracts]
TI: Ionospheric convection observations following the solar flare of 20 January 2005 and during the geomagnetic storm of 21 January 2005
AU: Holzworth, R H
EM: bobholz@ess.washington.edu
AF: University of Washington, Dept. of Earth and Space Sciences, Seattle, WA 98195 United States
AU: * Bering, E A
EM: eabering@uh.edu
AF: University of Houston, Department of Physics, Houston, TX 77204-5005 United States
AU: * Bering, E A
EM: eabering@uh.edu
AF: University of Washington, Dept. of Earth and Space Sciences, Seattle, WA 98195 United States
AU: Reddell, B D
EM: brandon.d.reddell@boeing.com
AF: University of Houston, Department of Physics, Houston, TX 77204-5005 United States
AU: Kokorowski, M
EM: mkoko@washington.edu
AF: University of Houston, Department of Physics, Houston, TX 77204-5005 United States
AU: Kokorowski, M
EM: mkoko@washington.edu
AF: University of Washington, Dept. of Earth and Space Sciences, Seattle, WA 98195 United States
AU: Bale, S
EM: bale@ssl.berkeley.edu
AF: University of California at Berkeley, Space Sciences Lab, CA 94720 United States, Berkeley, CA 94720 United States
AU: Blake, J B
EM: JBernard.Blake@aero.org
AF: Aerospace Corporation, Box 92957, Los Angeles, CA 90009-2957 United States
AU: Collier, A B
EM: colliera@nu.ac.za
AF: University of Natal, Physics Department, Durban, 4001 South Africa
AU: Hughes, A R
EM: hughes@nu.ac.za
AF: University of Natal, Physics Department, Durban, 4001 South Africa
AU: Lay, E
EM: erinlay@ess.washington.edu
AF: University of Washington, Dept. of Earth and Space Sciences, Seattle, WA 98195 United States
AU: Lin, R P
EM: rlin@ssl.berkeley.edu
AF: University of California at Berkeley, Space Sciences Lab, CA 94720 United States, Berkeley, CA 94720 United States
AU: McCarthy, M P
EM: mccarthy@geophys.washington.edu
AF: University of Washington, Dept. of Earth and Space Sciences, Seattle, WA 98195 United States
AU: Millan, R M
EM: Robyn.Millan@dartmouth.edu
AF: Dartmouth College, Dept. of Physics and Astronomy, Hanover, NH 03755 United States
AU: Moraal, H
EM: fskhm@puk.ac.za
AF: North-West University, School of Physics, Potschefstroom, 2520 South Africa
AU: O'Brien, T P
EM: Paul.OBrien@aero.org
AF: Aerospace Corporation, Box 92957, Los Angeles, CA 90009-2957 United States
AU: Parks, G K
EM: parks@ssl.berkeley.edu
AF: University of California at Berkeley, Space Sciences Lab, CA 94720 United States, Berkeley, CA 94720 United States
AU: Pulupa, M
EM: pulupa@ssl.berkeley.edu
AF: University of California at Berkeley, Space Sciences Lab, CA 94720 United States, Berkeley, CA 94720 United States
AU: Sample, J G
EM: jsample@ssl.berkeley.edu
AF: University of California at Berkeley, Space Sciences Lab, CA 94720 United States, Berkeley, CA 94720 United States
AU: Smith, D M
EM: dsmith@scipp.ucsc.edu
AF: University of California at Santa Cruz, SCIPP, Santa Cruz, CA 95064 United States
AU: Stoker, P
EM: fskphs@puk.ac.za
AF: North-West University, School of Physics, Potschefstroom, 2520 South Africa
AU: Woodger, L
EM: Leslie.Woodger@dartmouth.edu
AF: Dartmouth College, Dept. of Physics and Astronomy, Hanover, NH 03755 United States
AB: The MINIS balloon campaign was successfully conducted in January 2005 to investigate relativistic electron loss mechanisms. The MINIS campaign provided multi-point measurements of electron precipitation up to MeV energies, including simultaneous measurements at different longitudes and hemispheres. Two balloons, each carrying an X-ray spectrometer for measuring the bremsstrahlung produced as electrons precipitate into the atmosphere, were launched from Churchill, Manitoba. Four balloons, each carrying an X-ray spectrometer, and a 3-axis electric field instrument providing DC electric field and VLF measurements in 3 frequency bands, were launched from the South African Antarctic Station (SANAE IV). An X 7.1 solar flare occurred at 0636 UT on 20 January 2005. A CME from this flare arrived at the Earth 34 hours later. An SSC began at ~1650 UT followed by a geomagnetic storm with a Dst perturbation of ~-100nT. The AE index shows that the 20 January flare was followed first by 6 hours of deep quiet and then 28 hours of moderate activity. The balloon data contain evidence for two interesting geoelectric responses to the flare. The response of the tropospheric global circuit is discussed in a companion paper. There was an abrupt reduction of the horizontal electric field to a value near zero. Either the column resistance between the balloon and the ground fell to a value near zero, or the increased load from the ionosphere shorted out the cross-polar-cap potential. The arrival of the CME initiated an interval of very strong relativistic electron precipitation. The second and third Southern payloads and the first Northern payload made observations in both hemispheres of several extensive relativistic electron precipitation events that occurred from 1700 to 2000 UT on 21 January 2005. Each x-ray burst was preceded by a strong pulse of ionospheric convection. These flow bursts were directed poleward and sunward transport. The detailed comparison of data from the two balloons indicates that these bursts were temporal variations, not spatial structures. The data are consistent with an interval of enhanced reconnection and convection preceding each major enhancement in precipitation activity.
DE: 2712 Electric fields (2411)
DE: 2716 Energetic particles: precipitating
DE: 2730 Magnetosphere: inner
DE: 2794 Instruments and techniques
SC: SPA-Solar and Heliospheric Physics [SH]
MN: Fall Meeting 2005