Fig. 1From: Secondary instability generated on the equatorial plasma bubbles wall due to an interaction with midnight brightness waveThe airglow observatory at Bom Jesus da Lapa, Brazil, is represented by a black dot in the center of the black circle. The black circle denotes the field of view of the all-sky imager for the OI 630 nm emission, which has a radius of 9°. The black line shows the magnetic equator at 250 km altitude, while the magnetic field lines and quasi-dipole latitudes are represented by the red linesBack to article page