Ionospheric conductivity effects on electrostatic field penetration into the ionosphere

Abstract

Abstract. The classic approach to calculate the electrostatic field penetration, from the Earth's surface into the ionosphere, is to consider the following equation ∇· σ ·∇ =0 whereσ and are the electric conductivity and the potential of the electric field, respectively. The penetration characteristics strongly depend on the conductivities of atmosphere and ionosphere. To estimate the electrostatic field penetration up to the orbital height of DEMETER satellite (about 700 km) the role of the ionosphere must be analyzed. It is done with help of a special upper boundary condition for the atmospheric electric field. In this paper, we investigate the influence of the ionospheric conductivity on the electrostatic field penetration from the Earth's surface into the ionosphere.We show that the magnitude of the ionospheric electric field penetrated from the ground is inverse proportional to the value of the ionospheric Pedersen conductance. So its typical value in day-time is about hundred times less than in night-time.

Decrease of the electric field penetration into the ionosphere due to low conductivity at the near ground atmospheric layer

“…The model by Pulinets et al (1998) and further modifications of that model reviewed in Pulinets et al (2003) predict an electric field of about 1 mV m −1 in the ionosphere when a 100 V m −1 vertical electric field appears near ground. The model investigated by Denisenko et al (2008) predicts in the same case much less fields, 10 µV m −1 in the night time ionosphere and 0.1 µV m −1 at day time.…”

“…Particular interest is given to the conductivity profile near the ground and the electric field distribution at the Earth's surface. Our results are discussed and compared to the models of Pulinets et al (2003) and Denisenko et al (2008). It is shown that the near ground atmospheric layer with low conductivity decreases the electric field penetration into the ionosphere.…”

“…It excludes conductivity of the ionosphere in the model of Pulinets et al (1998Pulinets et al ( , 2000 and Kim et al (1996) and includes the integral conductivity of the ionosphere in the model by Denisenko et al (2008). Denisenko et al (2008) showed that the field penetration is inverse proportional to the value of the ionospheric Pedersen conductance, which is about 100 times less during nighttime than during day-time conditions. They concluded that the electric field penetration is damped and it is not possible to detect a seismic precursor signal at ionospheric heights, because larger electric fields of other nature always exist in the ionosphere.…”

“…For this approach they assumed straight and vertical geomagnetic field lines as well as a vertical electric conductivity profile of piecewise exponential functions. Several authors (Kim et al, 1994;Pulinets et al, 1998;Grimalsky et al, 2003;Denisenko et al, 2008) adapted their theoretical works on the penetration of electric fields into the ionosphere.…”

“…5) that the electric conductivity σ takes a major part in our investigations. In the model (Denisenko et al, 2008) the electric conductivity was presented with an exponential function of the height z…”