Fig. 2
From: Observation of equatorial plasma bubbles by the airglow imager on ISS-IMAP
The schematic figure of the selection of the EPB events. The top panel a shows the airglow image obtained on 25 September 2012. The middle panel b shows the model image of the tilted EPB as shown by an arrow in the top panel. To detect this EPB, the spatial variations of the airglow shown in the bottom panel c were sought