Electrodynamics of the ionosphere

Abstract

We review various important studies in the field of electrodynamics of the ionosphere. Four topics are presented; (1) conductivity, (2) wind and the dynamo theory, (3) drift and its effect on the ionosphere formation and (4) interaction between wind and electromagnetic field.We point out some important future problems. They are: (1) We need to consider in the dynamo theory of the geomagnetic daily variation the connection of the ionosphere of both hemispheres by lines of force of the geomagnetic field. (2) Non-periodic wind may be important for producing electric field. (3) Drift to cause interchange of ionization contained in tubes of the geomagnetic field lines, and diffusion of ionization in these tubes control dynamic lzehaviours of the F2 region. (4) Interaction between wind and electric current presents a new problem. (5) The ionosphere and the magnetosphere react to each other.

A Consideration on the Tidal Wave Transmission through the Ionized Atmosphere

“…Note, however, that the peculiar motion of ionization for such a high frequency is important in explaining various ionospherc behaviour (e.g. Maeda and Kato, 1966). The boundary between the high and the low frequency varies with height and time, but the maximum of a and a corresponds approximately to 1 hr (Fig.l) showing that a perturbation with longer period than 1 hr cannot be freely transmitted through the ionosphere; a strong reflection and absorption can be expected.…”

Detection of explosive events by monitoring acoustically-induced geomagnetic perturbations

“…In fact, Abbas (1968) has argued that hydromagnetic waves (AlfvCn waves) may also excite the Schumann resonances. We now recall that Gal'perin et al (1986) reported the detection of a magnetic impulse that they interpreted as an AlfvCn soliton generated by interaction of the neutral acoustic wave from the MASSA explosion with the dynamo (Rishbeth, 1971;Rishbeth, 1997;Maeda and Kato, 1966) portion of the ionospheric F region to produce strong field-aligned currents. (MASSA is the Russian acronym for "Magnetosphere-Atmosphere Coupling during Seismic Impact.")…”

Wave motions in the atmosphere and related ionospheric phenomena

“…Further, Tarpley (1970) found a current system induced by a given horizontal velocity with diurnal first negative mode ( Figure 13) to be very similar to that deduced from the geomagnetic Sq variations such as Chapman and Bartels (1940). Maeda, K. and Kato (1966), and Kato (1971) reviewed these problems in detail.…”

“…It is interesting to examine possible effects of this wind on the geomagnetic variations (van Sabben, 1962;Maeda, K. and Kato, 1966). If the rotation axis of the Earth coincides with that of the geomagnetic dipole and the wind velocity is constant with height, the total electric field is zero and hence the ionospheric current becomes zero provided no vertical leakage of the current occurs (Kato, 1957).…”

“…But the variation of the wind velocity with height results in inducing a ionospheric current, which amounts in some cases to a fairly large value (van Sabben, 1962). A similar situation may occur if the discrepancy between the rotation axis of the Earth's and the geomagnetic dipole axis is considered (Maeda, K. and Kato, 1966;Maeda, H. and Murata, 1968). Maeda, H. and Murata (1968) obtained some results showing that electric currents induced by non-periodic winds in the ionospheric produce Sq-like current systems changing with universal time and that the intensity of the main vortices is about one-tenth of that of the Sq field for a typical wind velocity of 10 m s-1.…”