Monochromatic ULF wave excitation in the dipole magnetosphere

Journal Article · Mon Apr 01 04:00:00 EST 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/90JA01592· OSTI ID:5258023

Lee, Donghun; Lysak, R L ^[1]

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1. Univ. of Minnesota, Minneapolis (USA)

Hydromagnetic waves are studied in the dipole manetosphere in the case when an almost monochromatic energy source is assumed to be located at the magnetopause. The wave spectrum is investigated through a fast Fourier transform and the wave structures are shown on the meridional plane. The authors have found that relatively large amplitude field line resonances (FLR) are produced only where the source frequency is matched to a harmonic of Alfven shear modes. On the other hand, the compressional wave spectra become rather broad banded. They suggest that boundary effects may be responsible for the broadening of these spectra. It is also suggested that the narrow bandwidth of the source plays an important role in determining the nature of the FLR excitations. These results may help to explain why compressional and transverse ULF wave spectra are often found to be broad banded even in the presence of a monochromatic source.

• OSTI ID: 5258023
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 96:A4; ISSN JGREA; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AMPLITUDES
COMPRESSION
DIPOLES
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ENERGY SOURCES
FOURIER TRANSFORMATION
HELMHOLTZ INSTABILITY
HYDROMAGNETIC WAVES
INSTABILITY
INTEGRAL TRANSFORMATIONS
MAGNETOPAUSE
MULTIPOLES
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
RESONANCE
SOLAR ACTIVITY
SOLAR WIND
SPECTRA
TRANSFORMATIONS