@article{oai:nipr.repo.nii.ac.jp:00002148,
 author = {Nishino,Masanori and Ungstrup,Eigil},
 journal = {Memoirs of National Institute of Polar Research. Special issue},
 month = {Mar},
 note = {P(論文), Electromagnetic waves at 10.2 and 13.6kHz from the Omega transmitter located in the northern Norway were observed on board four rocket payloads. Among these Omega signals, an unusual feature has been found for three payloads; the signals which ordinarily show double spin modulation of twice the rocket spin frequency were converted to single spin modulation in the altitude range of 70-115 km of the ionosphere, and the conversion took place for deep spin modulated signals with a weak intensity. It is concluded that the conversion was caused by a nonlinear effect of the Langmuir characteristic in the ionospheric plasma which indicated approximately a square root function.},
 pages = {26--35},
 title = {Nonlinear effect for the Omega signals in the auroral ionosphere by rocket observations},
 volume = {47},
 year = {1987}
}