Ionosphere F2-region under the influence of the evolutional atmospheric gravity waves in horizontal shear flow

• Published in: Journal of atmospheric and solar-terrestrial physics Vol. 61; no. 6; pp. 479 - 489
• Main Authors: Didebulidze, G.G., Pataraya, A.d.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-04-1999
• ISSN: 1364-6826; 1879-1824
• DOI: 10.1016/S1364-6826(99)00004-8

The ambipolar diffusion equation for the height distribution of electron density in the ionospheric F2-layer is solved in the presence of neutral horizontal shear flow. By using this nonstationary solution the reaction of the F2-region electron density on the evolution of atmospheric acoustic–gravity waves (AGW) is investigated. The evolution of the AGW and the corresponding behaviour of the height distribution of the F2-region electron density are described by the characteristic time,
t
a, of transient development of shear waves in the horizontal shear flow. For long times
t >
t
a, the gravity wave frequency tends to the isothermal Brunt–Väisälä frequency, which appears in the F2-layer as wavelike behaviour of
h
m
F2 and
N
m
F2 with periods close to 16–20 min, when the scale height of the neutral gas is
H = 60 km. The shear wave, which is due to the presence of horizontal shear flow, gives sufficient changes of the height profile of electron density for times of
t ⩽
t
a.