HR: 08:30h
AN: SA21B-03    [Abstracts]
TI: On Extreme Space Weather Conditions in the Equatorial Ionosphere
AU: Ilma, R R
EM: rhv5@cornell.edu
AF: Cornell University, School of Electrical and Computer Engineering, 351 Rhodes Hall, Ithaca, NY 14853, United States
AU: * Kelley, M C
EM: mikek@ece.cornell.edu
AF: Cornell University, School of Electrical and Computer Engineering, 351 Rhodes Hall, Ithaca, NY 14853, United States
AU: Vlasov, M N
EM: mv75@cornell.edu
AF: Cornell University, School of Electrical and Computer Engineering, 351 Rhodes Hall, Ithaca, NY 14853, United States
AU: Chau, J L
EM: jchau@jro.igp.gob.pe
AF: Radio Observatorio de Jicamarca, Instituto Geofisico del Peru, Apartado 13-0207, Lima, 13, Peru
AU: Valladares, C E
EM: cesar.valladares.1@bc.edu
AF: Boston College, Institute for Scientific Research, 412 St. Clement's Hall, 140 Commonwealth Avenue, Chestnut Hill, MA 02467, United States
AU: Nicolls, M J
EM: michael.nicolls@sri.com
AF: SRI International, Center for Geospace Studies, 333 Ravenswood Avenue, Menlo Park, CA 94025, United States
AU: Goncharenko, L P
EM: lgonchar@haystack.mit.edu
AF: MIT Haystack Observatory, Off Route 40, Westford, MA 01886, United States
AB: During the November 2004 Superstorm, unprecedented coverage was available from the radar chain near 75°W. In particular, the Jicamarca Radio Observatory reported the highest upward and downward drifts ever recorded. These huge upward drifts (>120 m/s) were highly correlated (90%) with the dawn-to-dusk component of the interplanetary electric field (the electric field in the frame of reference of the earth) with a 10% efficiency. When a reversal of the IEF abruptly occurred in daytime conditions, the temporal history of the zonal component of the equatorial field was similar but the efficiency was only about 3%. The huge daytime uplift abruptly evacuated the daytime ionosphere but the solar radiation immediately began to create a new ionosphere. With the above-mentioned reversal to downward motion, the high altitude plasma reappeared in the Jicamarca field of view, causing two F layers: one at 300 km and the other near 600 km. Equatorial spread F was suppressed by the northward turning of the IMF, but was initiated with the second episode of upward velocity over 120 m/s. A simple model of the ionospheric effects of these unusual drift patterns can only be reconciled with the data if, in addition to the penetrating electric field, an equatorward wind was also generated. Mid-latitude wind measurements at Millstone Hill and at Arecibo show that, indeed, several equatorward wind pulses were observed during the storm. Evidence for anomalous resistivity in the equatorial electroject will also be presented.
DE: 2415 Equatorial ionosphere
DE: 4239 Limnology (0458, 1845, 4942)
SC: SPA-Aeronomy [SA]
MN: 2007 Fall Meeting