Effects of charged sand on electromagnetic wave propagation and its scattering field

Abstract

Based on the Rayleigh's scattering theory, the effects of sandstorms on the propagation of electromagnetic wave with different visibilities are presented by solving the scattering field of charged sand particles. Because of the electric charges on the sand surface, the theoretical attenuation will be large enough to match the measured value under certain conditions. And the results show that the effect of sand with electric charges all over its surface on electromagnetic wave attenuation is the same as that of sand without charge, which proves that electric charges distribute on partial surface of the sand in fact.

Earth and Martian Sand and Dust Storms: A Comprehensive Review of Attenuation Modelling and Measurements

“…The accurate estimation of electric charge per unit area present on the SD particle is notoriously difficult to achieve, hence they are not publicly reported. Therefore, in literature, authors have used various parameters, such as the charge-to-mass ratio, to better To investigate the impact of charge distribution of SD particle on the EM wave attenuation the authors in [177] proposed a theoretical expression for EM wave attenuation in terms of dielectric permittivity, intensity of incident electric field, charge to mass ratio, frequency and visibility. Their results, obtained at 9.4 GHz, show that when the charge distribution angle is θ = π, the attenuation effect is the same as without charge.…”

Rayleigh approximation for the scattering of small partially charged sand particles

“…Some studies have reported that the larger sand gains net positive charge and the smaller sand gains net negative charge [13][14][15], and the charge-mass ratio reaches to 300 μC/kg [16]. Based on these investigations and the Rayleigh approximation, Zhou and co-workers first proposed a partially charged sphere model [12,17], and he found that the theoretical estimation can match the experimental value for the attenuation of incident waves while the considered sand particles gain reasonable charges that have been confirmed by field experiments. This research shows that the main reason for the long-standing problem that the measured decay value of the incident waves in sandstorms is much larger than the theoretical forecast is that the charges distributed on a particle's surface were ignored by previous researchers, and it is also the first study to reveal the cause.…”

Analysis of the forces acting on the saltating particles in the coupled wind-sand-electricity fields

“…Chinese scholars Liu and Yang [12] also concluded that the Magnus force and the Saffman force obviously influenced the sand particles' saltating trajectories. In addition to the four forces mentioned above, through experiments and theoretical studies, Zheng et al [13][14][15] proposed that, due to its own charged characteristics, the sand particles were influenced by a greater electrostatic force. Furthermore, some scholars [3,16] qualitatively compared the aerodynamic drag force, the Magnus force and the Saffman force with the gravity of the sand particles through experimental and theoretical analysis, and concluded that the aerodynamic drag force, which can be greater than or equal to the weight of sand, was the largest and most important, next was the gravity, and even smaller was the Saffman force ranging from 0.1% to 10% of gravity.…”