Electric field penetration into the ionosphere in the presence of anomalous radon emanation

The scientists came to consensus that electric field driven mechanism is more probable to explain ionospheric anomalies before earthquakes than the acoustic-driven mechanism (Pulients and Davidenko, 2014), and it is essential to understand how a vertical electric field from the ground penetrates into the ionosphere. Anomalous radon emanation in the epicentral area is believed to change the atmospheric electrical conditions. Considering the effect of radon emanation on atmospheric conductivity, the electric potential equation is established and solved numerically in the presence of a vertical electric field of 1 kV/m on the ground. The results show that radon emanation can strengthen atmospheric conductivity, as a consequence, the resulting electric field is increased by about 60% in the daytime ionosphere. However, the resulting electric field in the ionosphere is very weak (only about 0.3 μV/m), which implies that the penetration of vertical electric field of 1 kV/m in the seismic area is unlikely to produce daytime ionospheric anomalies before earthquakes.