Fig. 2From: EUV signals associated with O+ ions observed from ISS-IMAP/EUVI in the nightside ionospherePosition of the ISS for the period from 21:02 UT to 21:25 UT on December 26, 2012. The tip of an arrow indicates the tangential point at each time. The blue solid line on the map indicates the dip equator. The TEC value is shown with the color contourBack to article page