Physics
Scientific paper
Jan 1985
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1985georl..12...49k&link_type=abstract
Geophysical Research Letters (ISSN 0094-8276), vol. 12, Jan. 1985, p. 49-52.
Physics
204
Extremely Low Frequencies, Geomagnetic Pulsations, Magnetohydrodynamic Waves, Resonant Frequencies, Cold Plasmas, Coupled Modes, Transverse Waves
Scientific paper
Many important properties of ultra-low frequency (ULF) magnetic pulsations (about 1 to 10 minute periods) observed in the magnetosphere and by ground-based magnetometers have been interpreted successfully in terms of resonant field line models. These models describe the pulsations as transverse hydromagnetic waves standing on dipole flux tubes with fixed ends in the ionosphere. Signal structure and frequency are consistently explained, but the models fail to provide convincing explanations of the discrete spectra often observed. In this letter, it is proposed that the spectrum of excitations is dominated by frequencies that correspond to eigenfrequencies of the fast (compressional) mode in the outer magnetosphere. In the presence of plasma inhomogeneities, the eigenmodes of the fast mode damp, even in the absence of dissipation, through coupling to transverse waves. The properties of a damped eigenmode are discussed, pointing out the analogy to the properties of damped surface eigenmodes. The coupled waves exhibit field line resonance behavior on the magnetic shell where the transverse mode dispersion relation is satisfied, but the spectrum is dominated by fast mode eigenfrequencies.
Galland Kivelson Margaret
Southwood David J.
No associations
LandOfFree
Resonant ULF waves - A new interpretation does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Resonant ULF waves - A new interpretation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Resonant ULF waves - A new interpretation will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-926511