第6回極域科学シンポジウム[OS] 宙空圏11月16日（月）　国立極地研究所１階交流アトリウ

Allan Weatherwax

Ebihara Yusuke

Gerrard Andrew

Kadokuda Akira

Kanmae Takeshi

Motoba Tetsu

Ogawa Yasunobu

National Institute of Polar Research Repository

  Statistical study of dayside pulsating aurora  Takeshi Kanmae1, Tetsuo Motoba2, Yusuke Ebihara3, Yasunobu Ogawa1, Akira Kadokuda1,  Andrew Gerrard4, and Allan Weatherwax5 1National Institute of Polar Research, Tokyo, Japan 2The Johns Hopkins University Applied Physics Laboratory, Maryland, USA 3Research Institute for Sustainable Humanosphere, Kyoto University, Kyoto, Japan 4Center for Solar-Terrestrial Research, New Jersey Institute of Technology, New Jersey, USA 5Department of Physics, Siena College, New York, USA  Pulsating aurora normally occurs after a substorm breakup in the midnight sector, often observed to persist through the morning sector and beyond. Indeed, it has also been observed on the dayside; however, the characteristics of the dayside pulsating aurora are poorly known. A handful of observational studies have been reported, but the results are somewhat disputable because most of the studies had non-uniform sampling of the dark dayside region. Furthermore, the previous studies used photometer data, with which the spatial characteristics of the pulsating aurora cannot be examined. To determine both temporal and spatial characteristics of the pulsating aurora, we have studied three years of all-sky image data obtained at the South Pole station. Because of its unique geographical location, the station has 24 hours of darkness during the austral winter from April to August, providing an ideal platform for studying dayside aurora. In a preliminary survey of the data, we have identified the pulsating auroras in 198 days out of 365 days of observations. The magnetic local time (MLT) distribution of the occurrence peaks between 9:00 and 11:00, but shows no or little dependence on the geomagnetic activity. In many events, pulsating patches initially appear as east-west aligned arc segments and later in the afternoon sector develop into large, diffuse patches, which occasionally fill a large part of the field of view. Using the long-term data, we will statistically examine both temporal (occurrence rate, duration and pulsation period) and spatial (sizes and shapes) characteristics of the dayside aurora. 

Statistical study of dayside pulsating aurora

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Statistical study of dayside pulsating aurora

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