@article{oai:nipr.repo.nii.ac.jp:00004064,
 author = {Hayakawa, Masashi and Muto, Hiroyasu and Shimakura, Shin and Hattori, Katsumi and Parrot, Michel and Lefeuvre, Francois},
 journal = {Proceedings of the NIPR Symposium on Upper Atmosphere Physics},
 month = {Nov},
 note = {P(論文), The GEOS-1 satellite wave data have been used to determine the wave normal directions of chorus emissions in the off-equatorial region of the outer magnetosphere based on the wave distribution function method. The wave normal directions with respect to the magnetic field have been discussed as functions of wave frequency normalized by the local gyrofrequency and of the slope, df/dt of an emission. Two different kinds of chorus structures (rising tone and impulsive one) have been treated. A comparison of the present behaviour of off-equatorial wave normal directions with the previous equatorial wave normal measurements has enabled us to discuss the generation and propagation mechanism of chorus emissions with different structures (rising tone, falling tone, constant frequency tone and impulsive one), and finally we suggest the future problems to study.},
 pages = {62--73},
 title = {The wave normal directions of chorus emissions in the outer magnetosphere},
 volume = {2},
 year = {1989}
}