Monte Carlo Simulation Of Electromagnetic Wave Attenuation In The Charged Dust Particle System

With the rapid development of electromagnetic wave technology,radio wave,radar and remote sensing are widely used in atmospheric measurement.At sand/dust storm regions,electromagnetic wave technology is generally used to observe the visibility and particle density of sandstorm.These measurement techniques mainly take advantage of the scattering characteristics of electromagnetic waves,including the absorption,scattering and attenuation of electromagnetic waves caused by sandstorms.On the other hand,parameters such as dust visibility and sand surface charge will lead to attenuation of electromagnetic waves and thus affect the quality of electromagnetic signal and monitoring results.In order to ensure the accuracy and reliability of communication in dusty areas,this paper studies the scattering phase function of the charged dust particle system,the multiple scattering simulation and calculation of the dust particle system transmission,and the attenuation of the electromagnetic wave by the charged dust particle system.The main work is as follows:Firstly,based on Mie scattering theory,the scattering phase function and asymmetric parameters of the charged sand particle system are given,it is found that the scattering phase function of particles varies with the charge of particles and the incident frequency of electromagnetic waves,especially with the increase of the incident wavelength and the charge of the particles the backscattering phase function increases.The approximate expression of the scattering phase function,which is a function of the asymmetric parameters,is given by relating the phase function and the asymmetric parameters of charged particles.Then,we use Monte Carlo method to simulate the electromagnetic wave in the process of radiative transfer in dust medium,using the adjusted HG phase function to approximate the charged dust particle system of electromagnetic wave scattering phase function,derived after considering the multiple scattering of electromagnetic waves in dust transmission rate,thus Beer-Lambert's law was used to study the particle multiple scattering effect through the dust system of the electromagnetic wave attenuation.By comparing the transmittance of electromagnetic waves under the same conditions,only single scattering and multiple scattering of electromagnetic waves by particles are considered.It is found that when the visibility is low,the electromagnetic wave frequency is high and the distance between the particles and the dust system is long,the multiple scattering effect of the electromagnetic wave must be considered.Comparing the attenuation calculated by the two methods of single scattering and multiple scattering,the results show that the multiple scattering effect cannot be ignored when calculating and predicting the attenuation of electromagnetic wave in dust weather,especially in low visibility dust weather.The charged surface of particles affects the attenuation of electromagnetic wave.The larger the surface charge density of dust particles is,the greater the attenuation of electromagnetic wave will be.Moreover,the influence of charged surface of particles on the attenuation of electromagnetic wave is more significant at low frequency and small particle size.At the same time,we give the attenuation of electromagnetic wave signal transmitted between typical communication base stations in China,and the maximum visibility that needs to consider the multiple scattering effect of particles,which is a function of the particle charge and wave frequency.