HR: 0830h
AN: SM51C-0548    [PDF]
TI: Pi2 Pulsations With Second Harmonic: CRRES Observations in the Plasmasphere
AU: * Takahashi, K
EM: kazue.takahashi@jhuapl.edu
AF: Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723-6099 United States
AU: Anderson, R R
EM: roger-r-anderson@uiowa.edu
AF: Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 United States
AU: Hughes, W J
EM: hughes@bu.edu
AF: Department of Astronomy, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 United States
AB: Pi2 pulsations observed on the ground at low latitudes often exhibit multiple spectral peaks, and this property has been attributed to the harmonics of plasmaspheric cavity mode resonance. We show that multi-frequency Pi2 pulsations simultaneously observed from the Combined Release and Radiation Effects Satellite (CRRES) and at the Kakioka ground station (L = 1.26) can be explained by the cavity mode. The pulsations occurred in a 40-min time span on January 10, 1991. CRRES was within the plasmasphere at L = 6.1, on the dipole equator, and very near midnight. Kakioka was also very close to midnight. The pulsations consisted of two spectral components, ~7 mHz (f1, fundamental) and ~12 mHz (f2, second harmonic). At CRRES, the f1 oscillation was observed in the azimuthal component, Ey, of the electric field, while the f2 oscillation was observed in the compressional component, Bz, of the magnetic field. At Kakioka, by contrast, both the fundamental and second harmonic oscillations were detected in the horizontal component, H. The spectral separation between Ey and Bz implies that the spacecraft was located near the node/antinode of cavity mode resonance excited at multiple harmonics. Further support for this interpretation is provided from analyses of the phase of Ey and Bz.
DE: 2700 MAGNETOSPHERIC PHYSICS
DE: 2730 Magnetosphere--inner
DE: 2752 MHD waves and instabilities
DE: 2768 Plasmasphere
DE: 2788 Storms and substorms
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting