[P-EM10] Space Weather and Space Climate

[PEM10-26] Ionospheric convection associated with low-latitude auroras

*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：磁気圏、電離圏、低緯度オーロラ、SuperDARN

Low-latitude auroras, sometimes reaching up to the latitude of Japanese islands, have been witnessed by an increasing number of people recently, owing to the increasing solar activity and improvement of the sensitivities of handy-type cameras such as smartphones. On the contrary, the physical mechanisms of the low-latitude auroras have not yet been fully understood. Historically the low-latitude auroras were regarded as unstructured emissions, namely stable red auroral (SAR) arcs, due to the overlapping of the plasmasphere and ring current regions. However, recent observations of low-latitude auroras demonstrate that some of these emissions have structured characteristics, suggesting the presence of static electric fields. There have been relatively few observations of electric fields associated with low-latitude auroras, although. Estimating the electric field associated with low-latitude auroras is crucial for space weather studies, e.g., for estimating Joule heating during severe geomagnetic storms, which might affect the orbit change and atmospheric reentry of low earth orbit (LEO) satellites.

The deployment of the SuperDARN radars at mid-latitude in North America and Eastern Asia since 2005 enables us to study the detailed characteristics of the ionospheric electric fields associated with low-latitude auroras. In this paper, we report on the latest results of the relationship between low-latitude auroral precipitation during recent huge storms and ionospheric convection using the SuperDARN radars data (mainly those of the SuperDARN Hokkaido Pair of radars), optical imager data, and auroral particle precipitation data from LEO satellites.