HR: 0800h
AN: SM31B-1240    [Abstracts]
TI: Characteristics of Dayside Pi 2 Events During Magnetospheric Substorms
AU: * Martin, P A
EM: pmartin@pss.fit.edu
AF: Florida Institute of Technology, Department of Physics and Space Sciences, Melbourne, FL 32901 United States
AU: Moldwin, M B
EM: mmoldwin@igpp.ucla.edu
AF: UCLA, IGPP/ESS, Los Angles, CA 90095 United States
AU: Rassoul, H K
EM: rassoul@pss.fit.ed
AF: Florida Institute of Technology, Department of Physics and Space Sciences, Melbourne, FL 32901 United States
AU: Yumoto, K
EM: yumoto@geo.kyushu-u.ac.jp
AF: Kyushu University, Department of Earth and Planetary Sciences, Kukuoka, 812-8581 Japan
AU: Reeves, G
EM: reeves@lanl.gov
AF: LANL, Los Alamos, Los Alamos, NM 87545 United States
AB: Thirty-six isolated substorms were identified using the energetic electron flux from the LANL 1994-089 satellite. Ground-based magnetometer data was collected from the MM210 and MEASURE arrays to compare Pi 2 wave power and Pi 2 peak frequencies between the night and the daysides. Each substorm event was classified as combinations of Pi 2, Pc3, and Pc 4. Strong dayside Pi 2's were present in 25% of the events increasing to 83% for all categories of Pi 2. The amplitude of the night and day Pi 2 increases with L shell along the similar trend. The Night Pi 2 occurred between 2:00 and 3:00 a.m. putting them in the category of a flank Pi 2. The frequency of the night Pi 2 decreased with an increasing L shell and the night Pi 2, between an L = 1.0 and L = 2.5 showed a tendency for equality. The day Pi 2frequency occurred within 1.5 hours of local noon. The day Pi 2 frequencies also showed a tendency for equality between an L = 1.0 and L = 2.5. The median frequency for the low L shell day Pi 2, showed a similarity to the mid to high L shell night Pi 2. The majority of day Pi 2 appears to occur before the night Pi 2 approximately 20 minutes before the energetic particle injection of the substorm. A hint of a linear trend between solar wind dynamic pressure and the day Pi 2 suggests the day Pi 2 is a directly driven field line oscillation coupling with a cavity resonance mode minutes before a substorm.
DE: 7871 Waves and instabilities
DE: 7894 Instruments and techniques
DE: 2772 Plasma waves and instabilities
DE: 2788 Storms and substorms
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting