Electric currents flowing in the global electric circuit are closed by ionospheric currents. A model for the distribution of the ionospheric potential which drives these currents is constructed. Only the internal electric fields and currents generated by thunderstorms are studied, and without any magnetospheric current sources or generators. The atmospheric conductivity profiles with altitude are empirically determined, and the topography of the Earth’s surface is taken into account. A two-dimensional approximation of the ionospheric conductor is based on high conductivities along the geomagnetic field; the Pedersen and Hall conductivity distributions are calculated using empirical models. The values of the potential in the E- and F-layers of the ionosphere are not varied along a magnetic field line in such a model and the electric field strength is only slightly varied because the segments of neighboring magnetic field lines are not strictly parallel. It is shown that the longitudinal and latitudinal components of the ionospheric electric field of the global electric circuit under typical conditions for July, under high solar activity, at the considered point in time, 19:00 UT, do not exceed \(9\,\upmu {\text{V/m}}\), and in the sunlit ionosphere they are less than \(2\,\upmu {\text{V/m}}\). The calculated maximum potential difference in the E- and F-layers is \(42\,{\text{V}}\); the maximum of the potential occurs above African thunderstorms that are near the terminator at that time. A weak local maximum also exists above the thunderstorm area in Central America. The minimum potential occurs near midnight above the Himalayas. The potential has identical values at ionospheric conjugate points. The voltage increases to \(55\,{\text{V}}\) at 23:00 UT and up to \(72\,{\text{V}}\) at 06:00 UT, when local midnight comes, respectively, for the African and Central American thunderstorm areas. These voltages are about twice as large at solar minimum. With our more realistic ionospheric model, the electric fields are an order of magnitude smaller than those found in the well-known model of Roble and Hays (J Geophys Res 84(A12):7247–7256, 1979 ). Our simulations quantitatively support the traditional presentation of the ionosphere as an ideal conductor in models of the global electric circuit, so that our model can be used to investigate UT variations of the global electric circuit.

Seismogenic models have been recently proposed to explain precursors before earthquakes occurrences. Those models refer to physical processes linking the lithosphere, the atmosphere, and the ionosphere. We analyze in this work the curl‐free current model describing the current flow from the lithosphere to the ionosphere through the atmosphere. We use a numerical simulation based on the finite element method to derive the current between the ground and the ionosphere. We have shown that the curl‐free approximation of the atmospheric current density leads to significant and unpredictable distortions of the solutions of the electrical conductivity. Hence, it incorrectly expands the ionospheric disturbed region associated to lithospheric currents. It is shown that horizontally homogeneous vertical underground external currents cannot create currents from ground to the atmosphere.

Data on the atmospheric fair weather electric field obtained during Carnegie cruise VII are plotted as a two dimensional map in Universal Time and month co

Our colleague A. P. Nickolaenko has pointed out an unfortunate, and obvious, misprint in our paper. The error is in line 5 of page 12 showing values for s0, which corresponds to the value of the...

Due to the increase in radon emanation, the conductivity in the surface layer of air increases, which causes variations in the electric fields in the low atmosphere and according to some hypotheses in the ionosphere. There are well-known proposals on the possibility of using such ionospheric disturbances as precursors of earthquakes. In this study, the ionospheric electric fields are calculated in the framework of a quasi-stationary model of the conductor consisting of the atmosphere, including the ionosphere. The consequences of the paradoxical point of view on the decrease in the conductivity of surface air with an increase in radon content are also considered. It is shown that even with extreme radon emanation, the obtained calculated perturbations of the ionospheric electric field are three to four orders of magnitude smaller than the supposed precursors of earthquakes.