Inhomogeneous structure of ionospheric emission layers according to photographic observations at the Salyut-7 orbital station

Shape of brightness vertical profile for the ionospheric emission layers, observed near the night horizon from space vehicles, depends essentially on structure of luminescence regions. Brightness profiles, obtained from photometry of the first emission layer photons at ∼ 100 km heights, are compared with calculated ones for model distribution of the excited atom concentration to determine typical dimensions of heterogeneities. Luminescence region in the used model was represented by symmetric spot with concentration exponentially decreasing in horizontal direction and with vertical distribution of concentration characterized by rather abrupt maximum at ∼ 10 km height