Statistical study of magnetospheric ELF/VLF emissions simultaneously observed at Canada, Finland, and Syowa Station.
Abstract
We report first simultaneous ground-based observation of magnetospheric whistler-mode wave emissions in ELF/VLF ranges at Canada, Finland and Syowa station. We investigated spatial extent of the emissions by analyzing the data obtained at 3 longitudinally-separated stations in the auroral and subauroral latitudes, i.e., Athabasca (ATH), Canada (54.7N, 113.3W, magnetic latitude (MLAT): 61.3N), Kannuslehto (KAN), Finland (67.7N, 26.3E MLAT: 64.4N) and Syowa Station (SYO), Antarctica (69.0S, 39.6E, MLAT: 70.5S). Simultaneous data at these stations are available for total 48 days during December 10-14, 2012, January 9-19 and January 29-February 5, 2013, and February 26-March 21, 2014. We investigated average AE and Dst indices when ELF/VLF emissions were simultaneously observed. These indices were clearly higher than those when ELF/VLF emissions were observed at only one station. We also found that the absolute value of these indices increases with increasing the MLT separation of simultaneous observations. These results indicate that the longitudinal extent of ELF/VLF emissions increases with increasing geomagnetic activity. We found that simultaneous occurrence rate of the emissions at 2 stations is higher in the dayside sector, indicating that spatial extent of the emissions has MLT dependence. We also categorized ELF/VLF emissions into 2 types, which are chorus/hiss and quasi-periodic (QP) emissions. We found that the occurrence rate of QP emission at subauroral latitudes is higher than that at auroral latitudes.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMSM31A2475Y
- Keywords:
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- 6939 Magnetospheric physics;
- RADIO SCIENCEDE: 7845 Particle acceleration;
- SPACE PLASMA PHYSICSDE: 7867 Wave/particle interactions;
- SPACE PLASMA PHYSICSDE: 7959 Models;
- SPACE WEATHER