Fig. 7From: Longitudinal structure in electron density at mid-latitudes: upward-propagating tidal effectsLongitudinal and magnetic local time variations in the residual electron density (\(\Delta Ne\)) driven by migrating tidal non-wind effects (top), and the ratio between Oxygen and Nitrogen (\(\Delta O/N_2\)) at 400Â km in both hemispheres (bottom)Back to article page