Discontinuous Galerkin Time-domain Nodal Finite Element Analysis Of Electromagnetic Blackout Problems

Time domain finite element method is more and more popular in the field of computational electromagnetics because it can accurately simulate complex structures and process broadband signals.However,when the size of the target is larger than one wavelength,the time of solving the program will be greatly prolonged due to the matrix inversion.First,the discontinuous Galerkin time-domain finite element method based on vector basis function is introduced in this paper.Each element will form a separate local matrix,changing the shape of the global matrix so that the global matrix becomes block diagonal matrix,greatly reducing the inverse time.At the same time,discontinuous Galerkin time-domain finite element method allows different elements to use different order basis functions to interpolate the field values in each element.The fine structure can be based on the coarse mesh and high-order basis function.On the basis of ensuring the accuracy of the solution,the number of variables is reduced and the efficiency of the program is improved.Then,based on the vector finite element,the discontinuous Galerkin time-domain finite element based on node basis function is derived,which makes the node finite element method and vector finite element method unified.The discontinuous Galerkin node finite element method is applied to the analysis of electromagnetic wave propagation in plasma media.The existence of radio blackout is verified by the amplitude changes of input electric field and output electric field.Finally,the discontinuous time-domain node finite element method is applied to the practical engineering problems to analyze the problem of magnetic field alleviating the radio blackout(magnetic window problem).When a hypersonic vehicle is flying in a thin atmosphere,the shock wave will ionize the air and produce plasma sheath,which will severely attenuate the electromagnetic wave of communication.By studying the theory of reducing electron density by magnetic field,a magnetic fluid simulation model is established.The discontinuous Galerkin time-domain finite element method is used to discretize the fluid equation and the nonlinear Poisson equation.The electron density reduction under different conditions is analyzed by using the explicit time iteration method.