Global Electric Circuit (GEC) is the circuit that is formed between the surface of the Earth, which is a good conductor of static electricity, and the lower layers of the Ionosphere, which is a midly ionized plasma της Γης, at an altitude of ~ 80 km [Rycroft et al. Space Sci. Rev., 2008]. This spherical capacitor maintains in its armaments (Earth and Ionosphere) an average potential difference of 250 kV. The atmosphere between the capacitor armatures is a good conductor of electricity and its conductivity increases with height. The existence of conductivity is mainly due to the ionization of the neutral elements of the atmosphere by galactic cosmic rays, and therefore to the existence of positive and negative ions. Due to the potential difference and the conductivity of the atmosphere, an electric current flows through the circuit, which in terms of the total surface of the Earth is of the order of 1 kA. In order to maintain such a potential and therefore the continuous flow of electricity on a global scale, three electromotive forces are necessary: (a). Thunderstorms | Storm clouds, (b). the interaction between the Solar Wind and the Earth's Magnetosphere and (c). the dynamo effect created by atmospheric tides. Based the above, it becomes apparent that such a dynamic structure as the Earth's atmosphere is strongly electrified, with electrical properties that can affect any phenomenon that takes place within it.

Electrical processes could possible be a key factor in the life cycle of desert dust. Dust particles can be charged during transport, either by the attachment of atmospheric ions or by particle collisions (a trivoelectric effect). The measurements show that, on average, larger particles are positively charged while smaller ones are negatively charged [Zhao, H. L., J. Electrostat, 55, 2002; Lacks, D.J., et al., Phys. Rev. Lett., 100, 188305, 2008; Merrison, J.P., Aeolian Res., 4, 2012; Shinbrot, Τ. and Herrmann, H.J., Nature, 451, 2008]. When transporting dust, larger and mostly positively charged particles are separated from the smaller negatively charged particles due to gravitational precipitation, which classifies dust particles in size. This process develops vertical electric fields in the dust cloud, amplifying the pre-existing field due to the depletion of atmospheric conductivity by the presence of the dust layer [Gringel W. and Mulheisen. R., Beitr. Phys. Atmos., 51, 121–8, 1978]. Depending on its strength, the total electric field inside the dust cloud can: (a) compensate for the gravitational subsidence of large particles and (b) cause preference for non-spherical particles in the vertical direction that, in turn, affects the aerodynamics of the particles [Ulanowski, Z ., et al., Atmos. Chem. Phys., 7, 2007]. Therefore, electrical processes can change the processes of dust removal, and therefore the evolution of particle size during transport, affecting dust-radiation-cloud interactions and relative air quality. [Sajani S.Z., et al., Occup. Envirom. Med., 68 (6), 2011], weather and climate modeling [Mahowald, Ν., Et al., Aeolian Res., 15, 2014].

In this project, we will develop a new 3D Cartesian model that depends on time and will take into account several atmospheric processes, such as: (i) ionization due to the radiation of galactic cosmic rays (GCRs), (ii) ion-ion recombination and (iii) the attachment of ions to particles of non-spherical dust. The model will be able to consistently calculate the time dynamics of atmospheric conductivity and atmospheric electric field, in the presence of distribution of static non-spherical dust particles. In addition, the total load density, dust particle load and dust particle orientation will also be quantified. The new three-dimensional electrification formalization allows the study of dust layers without imposing symmetry and applies to layers with horizontal and vertical area, in contrast to the 1D models that apply when the horizontal extension is much larger than the vertical, or 2D models that have symmetry in the shape of the dust layer.

The results are comparable, in the limited case, that the horizontal area is much larger than the vertical, with those obtained from 1D models found in the previous literature [e.g. Zhou, L., Tinsley, B.A., Adv. Space Res. 50, 2012]. In addition, the effect of the studied electrification process must be approached by comparison with recent and unique measurements of electric field in dust layers, as is done by using new low-cost atmospheric electricity sensors in an experimental project of the project. D-TECT ERC , in Cyprus in November 2019.