[P-EM18] 磁気圏-電離圏ダイナミクス

[PEM18-09] トウィーク空電0次モード発生率の地方時・季節依存性

*大矢 浩代¹、荒木 徹、塩川 和夫²、三好 由純²、菊池 崇² (1.千葉大学大学院工学研究科、2.名古屋大学宇宙地球環境研究所)

Tweek atmospherics are VLF/ELF electromagnetic waves originated from lightning discharges and propagate in the Earth-ionosphere waveguide for long distances. So far, there are few studies for the zeroth-order mode of the tweeks. The preliminary reverse impulse (PRI) electric field of the geomagnetic sudden commencement (SC) is transmitted by the TM0 mode waves propagating at the speed of light in the Earth-ionosphere waveguide (Kikuchi et al., 1978; Kikuchi and Araki, 1979). In this study, we investigate the local time and seasonal dependence of the tweek zero-order mode to understand the characteristics of the zero-order mode. For statistical analysis, we developed the automatic detection procedure for the zero-order mode. In this session, we will discuss the results for the tweek zero-order mode in detail.