Study On Finite-difference Time-domain Method For Plasma And Electromagnetic Scattering Of Targets Coated With Reentry Plasma

The paper mainly researches finite-difference time-domain methods for plasma.The detailed derivation of the trapezoidal recursive convolution finite-difference time-domain(TRC-FDTD)algorithm for magnetized and non-magnetized plasmas is given.The model of reentry flight is given.And the electromagnetic scattering of typical targets coated with reentry plasmas is analyzed.Also the electromagnetic scattering of blunt cone coated with reentry plasma is analyzed.The main contributions of this dissertation are as follows:1.The TRC-FDTD algorithm is analyzed by using Maxwell's equations and the FDTD method.The method is proposed by Yee.A detailed derivation process is given.Corresponding examples is given to demonstrate the correctness and effectiveness of the proposed algorithm.2.The electromagnetic waves propagating in the magnetized plasma is studied by TRC-FDTD algorithm.The interaction between polarized electromagnetic waves in a random incident angle and magnetized cold plasmas is analyzed.When the direction of electromagnetic waves is parallel to the direction of magnetic field,the left circular polarized waves and the right circular polarized waves are calculated to get transmission coefficients and reflection coefficients.With the increase of the incidence angle,the reflection coefficient increase in a certain frequency domain.When the direction of electromagnetic wave is perpendicular to the direction of magnetic field,the extraordinary waves and the ordinary waves are analyzed and discussed.At the same time the influence of cutoff frequency is taken into consideration.3.The model of hypersonic blunt cone is established.The computational fluid dynamics method is used to obtain flow field of reentry plasma.The electromagnetic waves passing through the reentry plasma is studied and the influence of the position of reference point,the reentry speed,the reentry height,the thickness of plasma are studied by using TRC-FDTD algorithm.The corresponding radar scattering cross sections(RCS)of typical targets and blunt cone coated with reentry plasma are studied.And the influence of the position of reference point,the reentry speed,the reentry height,the cyclotron frequency and the thickness of plasma are analyzed.And the change of different parameters has an effect on the RCS of different targets...