[P-EM12] Coupling Processes in the Atmosphere-Ionosphere System

[PEM12-02] Longitudinal Range of Eastward-Traveling Equatorial Plasma Bubbles Inducing Ionospheric Scintillation

*Prayitno Abadi^1,2,3, Yuichi Otsuka¹, Susumu Saito⁴, Mamoru Yamamoto⁵, Septi Perwitasari⁶, Angga Yolanda Putra⁷ (1.Institute for Space-Earth Environmental Research (ISEE), Nagoya University, Nagoya, Japan, 2.Research Center for Climate and Atmosphere, Indonesian National Research and Innovation Agency (BRIN), Bandung, Indonesia, 3.School of Electrical Engineering, Telkom University, Kab. Bandung, Indonesia, 4.Electronic Navigaton Research Institute (ENRI), National Institute for Maritime, Port, and Aviation Technology (MPAT), Chofu, Tokyo, Japan, 5.Research Institute for Sustainable Humanosphere (RISH), Kyoto University, Kyoto, Japan, 6.National Institute of Information and Communications Technology (NICT), Tokyo, Japan, 7.Directorate of Laboratory Management Facilities and Science and Technology Park, Indonesian National Research and Innovation Agency (BRIN), Pontianak, Indonesia)

Keywords:Equatorial ionosphere, Equatorial plasma bubble, Ionospheric scintillation, GNSS, Space weather

Equatorial Plasma Bubbles (EPBs) are known to generate ionospheric irregularities that cause ionospheric scintillation at GHz frequencies used in the Global Navigation Satellite System (GNSS). EPBs can emerge at any longitude after local sunset and move in the same direction as the ambient plasma motion, usually eastward. Monitoring and predicting the occurrence of EPBs and scintillation for space weather services are essential. Our study uses data from three GNSS receivers positioned at almost the same latitude (~0°S) but separated in longitudes (~10°, ~16°, and ~25°) and the 47 MHz Equatorial Atmosphere Radar (EAR) in Indonesia to determine the longitudinal range of eastward-traveling post-sunset EPBs inducing ionospheric scintillation. Our research uncovers several findings. Statistically, scintillation occurrences detected by a ground receiver concentrate between sunset (~19 LT) and midnight (~01 LT). The occurrence rate of scintillation begins to rise at 19 LT, peaks at 21 LT, and then gradually decreases until it reaches its lowest point at 01 LT. By experimenting with pairs of GNSS receivers separated by longitude, scintillation events during this time frame (19–01 LT) are caused by EPBs originating within a longitudinal range extending up to 25° to the west of the receiver. Our further experiment, combining EAR and GNSS receiver data, suggests that the velocity of eastward-traveling EPBs decreases linearly from 187 m/s at 19 LT to 50 m/s at 01 LT. This means that the eastward-traveling EPB induces scintillation up to a longitudinal distance of approximately 25°, starting from the onset longitude at sunset to the midnight region in the east. Interestingly, both experiments infer a longitudinal range of 25° as the furthest extent for eastward-traveling EPB to generate scintillation from sunset to midnight regions. In conclusion, our research provides valuable insight into the ability of eastward-traveling EPB to induce ionospheric scintillation within a longitudinal range of 25°, thereby enhancing regional space weather services in scintillation monitoring and prediction.