Study On Interaction Between Charged Particles And Electromagnetic Waves

During the transport of particles,the surface of the particles is easily charged with a certain degree of charge,such as the dust particles charged during sandstorms,the volcanic ash particles charged during volcanic eruptions,the cloud droplets charged during thunderstorms,and the dust particles charged on industrial production lines.With the rapid development and wide application of electromagnetic wave technology,electromagnetic wave technology is widely used in the fields of monitoring the transport process of particle systems and detecting the properties of atmospheric particles.Moreover,in the process of wireless communication,electromagnetic waves often need to be transmitted in extremely harsh environments such as haze and dust.The detection results of electromagnetic waves on the particle system and the transmission quality of electromagnetic wave signals in harsh environments depend on the scattering and absorption of electromagnetic waves by the particles.Therefore,this thesis focuses on the scattering and absorption of electromagnetic waves by charged particles and the attenuation of electromagnetic waves propagating in extreme environments.The main research contents and research results are as follows:Firstly,based on the dynamic equation of the interaction between charged particles and electromagnetic waves,the equivalent dielectric constant model of locally charged particles under electromagnetic wave illumination is derived.The equivalent dielectric constant is a function of the electromagnetic wave frequency,the particle size,the surface charge density of the particles,and the charged area of the surface of the particle.When the electromagnetic wave frequency and the particle size are given,it is found that the imaginary part of the equivalent dielectric constant monotonously increases with the increase of the charged region and the surface charge density,and the real part of the equivalent dielectric constant is substantially unaffected by the surface charge of the particle.On this basis,in the Rayleigh scattering range,the relationship between the attenuation coefficient and the equivalent dielectric constant is used to study the attenuation law of the local charged particle system on electromagnetic waves.It was found that the attenuation of electromagnetic waves was significantly enhanced with the increase of the charged area and the surface charge density of the particles.In particular,when the radar system detects charged atmospheric particles,the influence of particle charging on radar echo power and the error of detecting particle concentration are studied.It turns out that the charged particles will increase the echo power of the radar system.The degree of enhancement is related to the frequency of the radar wave,the surface charge density of the particles,and the particle size.In addition,we also found that when the phenomenon of atmospheric particle charged is ignored,the concentration of the particle system based on radar echo power inversion may be overestimated.