@article{oai:nipr.repo.nii.ac.jp:00004045,
 author = {Hayakawa, Masashi},
 journal = {Proceedings of the NIPR Symposium on Upper Atmosphere Physics},
 month = {Feb},
 note = {P(論文), The GEOS 1 satellite observations of VLF/ELF waves in the off-equatorial region of the outer magnetosphere have indicated that the spectrum consists of upper and lower bands with a frequency gap between them. Based on the determination of wave normal directions of the upper band emissions in the off-equator and the subsequent inverse ray tracing toward the equator, it is found that the wave normal angles (θ) of the upper band emissions at the equator with respect to the magnetic field, are very close to the oblique resonance cone (θ_<res>) and that their normalized frequencies there are above 0.5. Hence, the upper band VLF emissions observed off the equator are identified as being "half-gyrofrequency" VLF emissions generated in the vicinity of the magnetic equator, with their wave normals close to θ_<res>, which lends further support to our previous equatorial conclusion. Also, their generation and propagation mechanisms are discussed.},
 pages = {168--172},
 title = {Direction finding of half-gyrofrequency VLF emissions in the off-equatorial region of the magnetosphere},
 volume = {1},
 year = {1988}
}