Fig. 9From: EUV signals associated with O+ ions observed from ISS-IMAP/EUVI in the nightside ionosphereEstimated omnidirectional flux of the 83.4 nm EUV at an altitude of 400 km on the nightside (in Rayleighs). The sunlit region at 400 km altitude is masked and only the flux in the umbra of the Earth is displayedBack to article page