[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

*Nozomu Nishitani¹, Tomoaki Hori¹, Keisuke Hosokawa², Atsuki Shinbori¹, Yuki Obana³, Mariko Teramoto⁴, Kazuo Shiokawa¹, Ryuho Kataoka⁵ (1.Institute for Space-Earth Environmental Research, Nagoya University, 2.Department of Communication Engineering and Informatics University of Electro-Communications, 3.International Research Center for Space and Planetary Environmental Science, Kyushu University, 4.Kyushu Institute of Technology, 5.National Institute of Polar Research)

Keywords: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.