@article{ed5c17a78a3e4732bc17d89d7e205fbf,
title = "Statistical Analysis of SAR Arc Detachment From the Main Oval Based on 11-Year, All-Sky Imaging Observation at Athabasca, Canada",
abstract = "We report the first statistical analysis of stable auroral red (SAR) arc detachments from the main auroral oval, using 630-nm all-sky cooled-Charge Coupled Device images obtained at Athabasca (magnetic latitude = 61.7°N), Canada. SAR arc detachments from the main oval can be an important way of monitoring the characteristics of ring current particle injection in the inner magnetosphere. We analyzed all-sky images obtained for 11 years from 2006 to 2016 and found 163 SAR arc detachment events. The SAR arc detachments tend to occur in the premidnight sector, indicating the ring current ion drift to the dusk sector. The SAR arc detachments also tend to occur at the beginning of the substorm recovery phase, suggesting that the SAR arcs detach from the main oval as the main auroral oval returns to higher latitudes. The equatorward velocities of detached SAR arcs are from −100 m/s (poleward) to +200 m/s (equatorward), corresponding to magnetospheric electric fields from −1 to +2 mV/m.",
keywords = "aurora, magnetic storm, plasmasphere, ring current, SAR arc detachment, substorm",
author = "Yuki Takagi and Kazuo Shiokawa and Yuichi Otsuka and Martin Connors and Ian Schofield",
note = "Funding Information: We thank Y. Katoh, H. Hamaguchi, Y. Yamamoto, and T. Adachi of ISEE, Nagoya University and Kyle Reiter of Athabasca University for their continuous support of the observation at Athabasca. The optical data obtained at Athabasca are available through ISEE. Quick-look plots of the optical data are available at http://stdb2.isee.nagoya-u.ac.jp/omti/. The construction and operation of the Athabasca University Geospace Observatory (AUGSO) were funded by the Canada Foundation for Innovation. The OMNI data were obtained from the GSFC/SPDF OMNIWeb interface at http://omniweb.gsfc.nasa.gov. The SYM-H, Ap, AU, and AL indices were provided by WDC-C2 for Geomagnetism at Kyoto University. F10.7 was provided by the Natural Resources Canada. This work was supported by grants-in-aid for Scientific Research (15H05815 and 16H06286) provided by the Japan Society for the Promotion of Science. Funding Information: We thank Y. Katoh, H. Hamaguchi, Y. Yamamoto, and T. Adachi of ISEE, Nagoya University and Kyle Reiter of Athabasca University for their continuous support of the observation at Athabasca. The optical data obtained at Athabasca are available through ISEE. Quick-look plots of the optical data are available at http://stdb2.isee. nagoya-u.ac.jp/omti/. The construction and operation of the Athabasca University Geospace Observatory (AUGSO) were funded by the Canada Foundation for Innovation. The OMNI data were obtained from the GSFC/SPDF OMNIWeb interface at http://omniweb.gsfc.nasa.gov. The SYM-H, Ap, AU, and AL indices were provided by WDC-C2 for Geomagnetism at Kyoto University. F10.7 was provided by the Natural Resources Canada. This work was supported by grants-in-aid for Scientific Research (15H05815 and 16H06286) provided by the Japan Society for the Promotion of Science. Publisher Copyright: {\textcopyright}2018. American Geophysical Union. All Rights Reserved.",
year = "2018",
month = nov,
day = "16",
doi = "10.1029/2018GL079615",
language = "English",
volume = "45",
pages = "11,539--11,546",
number = "21",
}