Stochastic FDTD Method And Its Application In Plasma Sheath

The electrical parameters of many media in nature ofen have random characteristics,and the characterristics of electric wave propagation in the random media have always been of concern.Monte Carlo method as a criterion methad has been widely used to study the statisicalcharacteristcs of radio wave propagation in random meidia.However,this method needs to calulate a Large mumber of sanmples to obtain the statistical properties of the field(mean andvarianze).When the Finite-Difference Time-Domain(FDTD)method is used to calculate each sample,the single FDTD consuming is largce,Compared with the stochastic Finite-Difference time-domain S-FDTD deceloped in recent years,stochastic Finite-Difference time-domain(S-LFDTD)dierctly substitutes the stochastic properties(varinces)the medium into tht electromagnetic field iteratiom.the statistical properties of the field value can be obtained by only one calculation,which significantly improves the computational efficiency.In this paper,the S-FDTD method and its absorbing boundary are studied in detail.The S-FDTD method for the ordinary medium has been extended to the dispersive medium,and the influence of the random characteristics of electron density in plasma sheath on electric wavepropagation is analyzed.The main work of this paper is as follows:1.The SC-PML absorbing boundary condition is applied to the S-FDTD,which improves the absorption efffect of the Mur boundary to the standard deviation of the field value in the traditiona S-FDTD method.2.By combining the S-FDTD method with the Piecewise Linear Recursive Convolution(PLRC)method in dispersive media,the S-PLRC-FDTD method suitable for dispersive media ispropoed.The correctness of the algorithm is verified by comparison with Monte Carlo method,3.The S-PLRC-FDTD method is used to analyze the impacts of the random variation of the electron density in the plasma sheath on the radio wave characteristics.The applicability of the S-FDTD method and the statistical characteristics of the radio wave propagation are analyzeddetailed when different variances of the plasma frequency were used.The results show that the proposed S-PLRC-FDTD method can be used to evaluate the propagation characteristics of electromagnetic waves in plasma sheaths effectively.