A Realization Method of Fully Matching Absorption Boundaries of Extended Coordinates in Plasma

Abstract

The invention discloses a method for realizing a perfectly matched absorbing boundary of expanding coordinates in a plasma. The method comprises the following steps of inputting a model file; initializing parameters and setting a PML (perfectly matched layer) coefficient and an absorbing boundary parameter; updating and calculating the magnetic field component coefficient H<q>(z) of the whole calculation area, adding a field source to an electric field component coefficient E<q>(y), updating and calculating the electric field component coefficient E<q>(y) of the whole calculation area, updating and calculating the electric field component coefficient E<q>(x) of the whole calculation area, updating and calculating the electronic average speeds U<q>(ex), U<q>(ey) of the whole calculation area, and updating and calculating the auxiliary variables of the electric and magnetic field component coefficients of the whole calculation area; calculating electric and magnetic field components at an observing point; assigning q+1 to q, judging whether q reaches a preset value or not, and if q does not reach the preset value, returning to step 3; if q reaches the preset value, ending. According to the method for realizing the perfectly matched absorbing boundary of the expanding coordinates in the plasma, due to the fact that the absorbing boundary can be very conveniently combined with parameters in CFS factors, the method has better absorbing effect on low frequencies and evanescent waves.

Description

technical field [0001] The invention belongs to the technical field of computational electromagnetism, and relates to a method for realizing fully matching absorption boundaries of extended coordinates in plasma. Background technique [0002] The Finite-difference time-domain (FDTD) method is widely used in the simulation of electromagnetic wave propagation in dispersive media because of its simple implementation. However, its time step is limited by the Cauchy stability condition, which limits the application of the FDTD method to fine-structure models. In order to eliminate the limitation of the Cauchy stability condition, unconditionally stable finite-difference time-domain methods have been proposed, such as: Alternating-Direction-Implicit (ADI) finite-difference time-domain (ADI-FDTD) method and weighted-based Laguerre polynomials Finite-difference time-domain (WLP-FDTD) method. Among these methods, the ADI-FDTD method will produce a large dispersion error when using ...

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Problems solved by technology

Someone proposed a perfectly matched layer (Perfectly matched layer, PML) absorption boundary. Later, PML was widely used to calculate the truncation of the area, and it was proved to be very effective. However, the research found that the traditional PML has an absorption effect on low frequencies and litter waves. Not ideal; using a PML (CFS-PML) absorption boundary with a complex frequency shift (CFS) factor can effectively improve the traditional PML's absorption effect for low frequencies, litter waves and glancing situations

Recently, someone proposed a WLP-FDTD method using an auxiliary differential equation with an approximately perfectly matched absorption boundary to solve the electromagnetic field problem in a dispersive medium. The absorption effect of this approximately completely matched absorption boundary is not very ideal, and there are error

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