Auroral O+ 732/733 nm emission and its relation to ion upflow

• Main Authors: Naoko Koizumi, Shoichi Okano, Takeshi Sakanoi, Makoto Taguchi, Takehiko Aso
• Format: Report
• Language: English
• Published: Planetary Plasma and Atmospheric Research Center, Tohoku University/Planetary Plasma and Atmospheric Research Center, Tohoku University/Planetary Plasma and Atmospheric Research Center, Tohoku University/National Institute of Polar Research/National Institute of Polar Research 2004
• Subjects: aurola; oxygen ion; upflow; ESR; Svalbard; Longyearbyen; EISCAT; Advances in polar upper atmosphere research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=6384; http://id.nii.ac.jp/1291/00006384/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=6384&item_no=1&attribute_id=18&file_no=1

Observations of auroral oxygen ion emission at 732/733 nm were made at the Aurora station in Longyearbyen (78.2.N, 16.3.E; lm=74.9.) using an all-sky spectrograph (ASG) during the winter season of 2000/2001. A statistical analysis showed that the highest occurrence of oxygen ion auroras at Longyearbyen was seen in the dayside of the 09-12MLT region; the intensities of these auroras were also larger than those on the night side. To study the mechanism of ion up゜ow in the polar ionosphere, ASG data obtained on December 7, 2000, was analyzed together with simultaneous ionospheric data obtained by EISCAT Svalbard radar (ESR). Enhancements of electron temperature and ion upward velocity were associated with an increase in the auroral OII intensity at the magnetic zenith. This result suggests that an ambipolar electric field associated with electron temperature enhancement caused by soft electron precipitation may be involved in the mechanisms that drive ionospheric ions upward.