Analysis On Electromagnetic Characteristics Of Magnetic Time-varying Plasma By Using FDTD Method

Plasma is a kind of complex medium with special properties,which has been the focus of scholars since it's discovery.In recent years,with the extensive application of plasma in materials,information,energy,chemical industry,military industry,aerospace and other fields,it is particularly important to further study plasma,especially in the electromagnetic characteristics of plasma,which has a profound significance and research value for the development of implicit technology,aircraft,national defense and other aspects.In this paper,the propagation characteristics of electromagnetic waves in magnetized time-varying plasma are analyzed by using time-domain finite difference method,and the relevant conclusions are obtained.Firstly,the current density Laplace time-domain finite difference method(CDLT-FDTD)is introduced,which is suitable for magnetized time-invariant plasma.The validity of such algorithm is verified by calculating the reflection coefficient of electromagnetic wave in one-dimensional time-invariant magnetized plasma plate.Then,the current density convolution time domain finite difference method(LTJEC-FDTD)based on Laplace transform current density convolution for one-dimensional and three-dimensional magnetized time-varying plasma is derived.The numerical results of electromagnetic wave reflection coefficient under one-dimensional magnetized time-varying plasma are compared with the analytical results,and the correctness and high efficiency of such algorithm is verified.Compared with ordinary FDTD algorithmic in magnetic time-varying plasma,LTJEC-FDTD has simpler iterative formulas and higher computational efficiency.Moreover,this FDTD algorithmic deals with the complex convolution perfectly and has a wider application range.Secondly,the variation of output frequency with the initial value of plasma frequency and electron gyro frequency is studied.The conclusion is drawn that the frequency cut-off,the frequency up-shift and the frequency constant will occur in different frequency ranges.And in magnetic time-varying plasma,the sampling results of the electric field components are simulated by LTJEC-FDTD.The variation of the output amplitudes with different the initial value of the plasma frequency and the electron rotation frequency is analyzed.Then,the propagation of Whistler standing wave in one-dimensional magnetized time-varying plasma is further analyzed in detail.By simulating the variation of electromagnetic component and magnetic field component in time domain and frequency domain,the results show that when the Whistler standing wave propagating in magnetized time-varying plasma,the frequency get promoted,the electric field is strengthened,the magnetic field is weakened and the polarization mode remains unchanged.Moreover,by changing the parameters and comparing the simulation results,the influence of plasma parameters on electromagnetic propagation is analyzed.Finally,by using the above conclusions,a 0.3 THz terahertz wave is obtained by adjusting the parameters to further increase electromagnetic frequency,which provides some guidance for the generation of terahertz wave sources.