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

[PEM12-15] Characteristics of ionospheric convection associated with low-latitude auroral emission during high geomagnetic activity

*西谷 望¹、堀 智昭¹、細川 敬祐²、新堀 淳樹¹、尾花 由紀³、寺本 万里子⁴、塩川 和夫¹、片岡 龍峰⁵ (1.名古屋大学宇宙地球環境研究所、2.電気通信大学大学院情報理工学研究科、3.九州大学国際宇宙惑星環境研究センター、4.九州工業大学、5.国立極地研究所)

キーワード：low-latitude aurora、SuperDARN、convection、flow shear

During periods of severe geomagnetic activity, auroras can be observed at much lower geomagnetic latitudes than the average auroral oval, e.g., lower than 40 degrees. Although several papers discussed the possible generation mechanisms for these auroras, their relationship with the ionospheric plasma convection pattern or the electric field distribution is poorly understood, mainly because there was little observation data.

The SuperDARN Hokkaido East and West radars, located at the lowest geomagnetic latitude at present, have been operating since 2006 and 2014, respectively, and observed ionospheric plasma convection patterns for three events in March 2015, November 2023, and December 2023, during which low-latitude aurora was observed in Rikubetsu, Hokkaido, Japan (geomagnetic latitude: 37 degrees). The radar observations generally show that the low-latitude auroral precipitation regions are accompanied by sheared east-west ionospheric flows, although the detailed flow pattern differs for each event. More detailed analysis results, discussion, and interpretation of these plasma flow patterns associated with the low-latitude auroras will be presented.