The midlatitude ionosphere D-region response to some events on the sun Original Research Article

We investigated reactions of the middle latitude ionospheric D-region to geomagnetic sudden storm commencements, to solar flares and to bursts of radio frequency radiation. Such events are, as a rule, accompanied by precipitation of the high energy electrons and protons, leading to short-term (of the order of units-tens of minutes) increases by about 50–200% (sometimes more) of the electron density both in the lower (z < 75 km) and in the upper (z > 75 km) middle latitude D-region. Such processes in this height range are accompanied by the generation and enhancement of acoustic-gravitational waves with periods of about units of minutes and characteristic duration of 10–30 min. At the same time, the electron density increases by 50–200%, and quasi-harmonic changes in the height-time N(z, t) variations were observed.