Morphology of storms in the ionosphere

Abstract

A review is given on the morphology of storms in the ionosphere based on the results obtained during the world-wide cooperative observations, IGY (1957-1958) and IGC (1959). Ionospheric disturbances are classified into two categories: disturbances that take place in the lower ionosphere and F region ionospheric storms. E region disturbances are mainly caused by an abnormal ionizing agent penetrating into the lower ionosphere. Sudden ionospheric disturbances are due to an outburst of solar X rays associated with chromospheric flares, while polar blackout phenomena are produced by incoming energetic particles. It is shown that solar cosmic ray particles (sub-relativistic) ejected from an intense flare are the source of a prolonged blackout in the polar cap region, known as polar cap absorption, and auroral particles consisting presumably of energetic electrons are responsible for auroral blackouts. Average features of these two types of polar blackout are described in some detail with other related geophysical phenomena. © 1964, Society of Geomagnetism and Earth, Planetary and Space Sciences. All rights reserved.