Conduction current and extraneous electric current in the global electric circuit

Seismogenic Disturbances of the Ionosphere During High Geomagnetic Activity

“…GPS observations also show the strong positive TEC disturbances exceeding 80% and located northeast of the epicenter. They are similar to the seismogenic disturbances reported in [6,7], with the exception of the magnetic conjugation and daytime appearance. An increase in the vertical electric currents does not lead to the appearance of the strong positive TEC disturbances in that area in either the UAM-T or the UAM-M calculations.…”

“…In the present calculations, two current density values were used: j s = 20 nA/m 2 and j s = 40 nA/m 2 . The last value is 1000 times higher than the fair-weather currents and about the same order of magnitude as the thunderstorm currents densities [7]. In the calculations of present model for the period from 25 December 2015 to 3 January 2016, including the disturbances of December 31-January 1, we used the spatial distribution of the FACs dependencies on AE and Kp as described above and the spatial distributions of the precipitating electron fluxes depending on Kp according to the statistical model of auroral electron precipitation [4].…”

“…In the previous UAM calculations [6,7,[9][10][11], where the middle-latitude earthquakes were simulated, the main cause of the TEC disturbances was attributed to the electrostatic electric field generated as a result of the seismogenic vertical electric current. The electrostatic field was directed radially from the epicenter in the case where the electric currents flow to the ionosphere, and toward the epicenter for the currents of the opposite direction.…”

“…The seismogenic electric currents j s were added to the potential equation locally, above the Indian earthquake epicenter. Previously, j s = 20 nA/m 2 has been used as the density of the vertical electric currents in the UAM numerical calculations for the middle-latitude earthquakes which occurred during quiet geomagnetic activity, and the TEC disturbances were~40% relative to the non-disturbed values [6,7]. The chain of electric current sources with the length of 4000 km was setup along the tectonic fault, parallel to 30 • meridian.…”

Ionospheric Precursors Observed in TEC Due to Earthquake of Tamenglong on 3 January 2016

“…This electric field can penetrate into the ionosphere and create perturbation in the electron density by E  B plasma drift mechanism 22 . In previous studies it was shown that seismic activity leads to an increase in the quasi-static electric field in the ionosphere which reaches ~10 mV/m, while its value on the earth's surface is ~100 V/m 23,24 . The field is localized in the ionosphere over the epicentre area, as well as, the related region with a characteristic horizontal scale of 100 to 1000 km depending upon magnitude of earthquake.…”