Midsummer decrease in vertical geomagnetic field at the magnetic pole under strong solar radiation into the polar ionosphere

• Main Author: Naoshi Fukushima
• Format: Report
• Language: English
• Published: Institute of Earth and Planetary Physics, University of Tokyo 1999
• Subjects: EISCAT; Geomagnetic Pole; Advances in polar upper atmosphere research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=6287; http://id.nii.ac.jp/1291/00006287/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=6287&item_no=1&attribute_id=18&file_no=1

The vertical component of the geomagnetic field Z on the ground shows a noticeable decrease in midsummer, amounting to several tens of nT, in the polar region at and around the geomagnetic pole. This peculiar phenomenon seems to be attributable to the eastward Hall current in the sunlit polar ionosphere at the lower E region produced by the perpetual eastward neutral wind in the summer season, which is recently detected with the EISCAT experiment.