@article{oai:nagoya.repo.nii.ac.jp:00024763,
 author = {Yonezu, Yusuke and Shiokawa, Kazuo and Connors, Martin and Ozaki, Mitsunori and Manninen, Jyrki and Yamagishi, Hisao and Okada, Masaki},
 issue = {6},
 journal = {Journal of Geophysical Research-Space Physics},
 month = {Jun},
 note = {To investigate longitudinal extent of electromagnetic wave activity, we report the first simultaneous ground-based observations of magnetospheric ELF/VLF emissions at the following three longitudinally separated stations at auroral and subauroral latitudes: Athabasca, Canada (ATH; magnetic latitude: 61.3°N); Kannuslehto, Finland (KAN; 64.4°N); and Syowa Station, Antarctica (SYO; 70.5°S). The magnetic local time (MLT) separations of SYO-KAN, ATH-SYO, and ATH-KAN, are 3, 8, and 11 h, respectively. Simultaneous observation data at these stations are available for a total of 48 days in 2012–2014. The simultaneous occurrence rates of ELF/VLF emissions are 9.8%, 2.5%, and 3.6% for SYO-KAN, ATH-SYO, and ATH-KAN, respectively. We found that the simultaneous wave occurrence rate between two stations is higher in the morning-dayside sector, indicating that the longitudinal extent of the emissions exhibits MLT dependence. When emissions are simultaneously observed at two stations, the average AE and |Dst| indices tend to be higher. Similarly, if the two stations are more separated in MLT, the average |Dst| index increases. These results suggest that the longitudinal extent of ELF/VLF emissions increases with increasing geomagnetic activity.},
 pages = {6442--6454},
 title = {Simultaneous observations of magnetospheric ELF/VLF emissions in Canada, Finland, and Antarctica},
 volume = {122},
 year = {2017}
}