Distribution of ULF energy (f < 80 mHz) in the inner magnetosphere: A statistical analysis of AMPTE CCE magnetic field data

Journal Article · Wed Jul 01 04:00:00 EDT 1992 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/92JA00328· OSTI ID:7158405

Takahashi, Kazue; Anderson, B J ^[1]

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1. Johns Hopkins Univ., Laurel, MD (United States)

The distribution of ULF energy (frequency < 80 mHz) in the inner magnetosphere (L = 2.5-6.5) has been studied using magnetic field measurements made with the Active Magnetospheric Particle Tracers Explorers Charge Composition Explorer (AMPTE CCE) spacecraft during its whole mission of over 4 years. The magnetic field time series was split into consecutive 10-min segments and subjected to fast Fourier transform (FFT), and the spectral data were achieved along with the Kp index and the satellite location. This data base was then used to examine the spatial distribution of ULF energy. Overall, the oscillation energy is localized to the dayside except for compressional oscillations associated with substorms. From the spatial distributions of wave power and spectral structures the authors identify several pulsation types, including multiharmonic toroidal oscillations; equatorial compressional Pc 3 oscillations; second harmonic poloidal oscillations; and nightside compressional oscillations; equatorial compressional Pc 3 oscillations; second harmonic poloidal oscillations; and nightside compressional oscillations. The toroidal oscillations are observable even in the plasmasphere, and using their frequencies they can determine the statistical radial profile of the plasma mass density and Alfven velocity. They find a clear signature of the plasmapause in the profiles of these average parameters. Of particular interest among the other oscillation types are the equatorial compressional Pc 3 oscillations that have an average spectral peak around 30 mHz and are present in the prenoon sector and from L{approximately}3 to {approximately}5. The oscillations are similar to the compressional Pc3 previously observed at and near geostationary orbit and might represent magnetohydrodynamic waves propagating from the parallel portion of the bow shock.

• OSTI ID: 7158405
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 97:A7; ISSN JGREA; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
&amp; Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COLLISIONLESS PLASMA
DISTRIBUTION
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
EXPLORER SATELLITES
HYDROMAGNETIC WAVES
INTERACTIONS
MATHEMATICS
PLASMA
PLASMA DENSITY
PLASMASPHERE
SATELLITES
SHOCK WAVES
SOLAR ACTIVITY
SOLAR WIND
SPATIAL DISTRIBUTION
TIME-SERIES ANALYSIS