What we can learn from measurements of air electric conductivity in ²²²Rn‐rich atmosphere

Abstract

Electric conductivity of air is an important characteristic of the electric properties of an atmosphere. Testing instruments to measure electric conductivity ranging from~10 −13 to 10 −9 Sm −1 in natural conditions found in the Earth atmosphere is not an easy task. One possibility is to use stratospheric balloon flights; another (and a simpler one) is to look for terrestrial environments with significant radioactive decay. In this paper we present measurements carried out with different types of conductivity sensors in two 222 Rn-rich environments, i.e., in the Roselend underground tunnel (French Alps) and in the Institute of Radioprotection and Nuclear Safety BACCARA (BAnC de CAllibrage du RAdon) chamber. The concept of the conductivity sensor is based on the classical time relaxation method. New elements in our design include isolation of the sensor sensitive part (electrode) from the external electric field and sensor miniaturization. This greatly extends the application domain of the sensor and permits to measure air electric conductivity when the external electric field is high and varies from few tens of Vm −1 to up to few tens of kVm −1 . This is suitable to propose the instrument for a planetary mission. Two-fold objectives were attained as the outcome of these tests and their analysis. First was directly related to the performances of the conductivity sensors and the efficiency of the conductivity sensor design to shield the external electric field. Second objective aimed at understanding the decay mechanisms of 222 Rn and its progeny in atmosphere and the impact of the enclosed space on the efficiency of gas ionization.

Slide electrification: charging of surfaces by moving water drops

“…At sea level, air has a typical conductivity of 10 À14 S m À1 . [54][55][56] Though discharging in air may be slow, it is the only option for substrates like Teflon. If we denote the relaxation time for discharging through air by t a , the total relaxation time for discharging is 1/t = 1/t e + 1/t a .…”

What We Can Learn from the Electric Field and Conductivity Measurements in Auroral Atmosphere

“…A simplified schematic of the SDA electrical configuration, relationship between the measured potential and that found at the electrode level and also the relationship between the coupling resistance and the air electric conductivity were discussed in details in our previous publications, i.e. Seran et al [2013 and2017]. Here, we briefly summarize the main findings.…”

“…It reads as: Even if this parameter was measured during entire flight, the most points depicted in the Figure correspond to the observations performed in the stratosphere. The reasons of this are discussed in our previous paper [Seran et al, ] and are related to the limitations of the relaxation method. The method works well when the electric field produced by the potential applied to the electrode in the initial phase of the relaxation measurements is significantly higher than the ambient DC and AC (continuous and alternative) electric field.…”

“…In the first case, the air ionization is produced by galactic cosmic rays and solar energetic particles (see, for example, Nehar, 1967;Reitz, 1993;Viggiano & Arnold, 1995;Singh et al, 2011;Iles et al, 2004). In the second case, the ions of both polarities are generated by a decay of the 222 Rn gas emitted from the surrounding rocks (see, for example, Richon et al, 2005, Seran et al, 2017. In the first case, the radiation level varies with the solar activity, atmospheric height, geomagnetic latitude and solar zenith angle.…”

Influence of Meteorological Variables on Atmospheric Electric Conductivity over an Urban Location

“…With reference to the altitude, the electric conductivity of air gradually grows from ~10 −15 to ~10 −10 Sm −1 , while the vertical electric field decreases from ~10 2 to ~10 -2 Vm −1 from ground level to upper stratosphere. Electric conductivity of the atmosphere, which characterizes its ability to conduct an electric current, is mainly due to cosmic rays, UV radiations and radioactive isotopes [5]. The contribution of cosmic rays and UV radiation is dominant above troposphere and the variation in ionization of air near the ground is mainly due to alpha particles during radioactive decay of 222 Rn and its progenies.…”