Simulation Of Electromagnetic Wave Propagation In Plasma Using PIC Method

When aircraft flight in the atmosphere with hypersonic speed, the aircraft surface will produce a layer of plasma layer due to the intense friction between aircraft surface and atmosphere, known as the plasma sheath. The plasma sheath are rich in interaction with the incident electromagnetic wave, such as absorption, attenuation, reflection, refraction, etc. From a positive point of view, we can use the interaction between plasma sheath and electromagnetic wave to realize plasma stealth; from a negative point of view, the plasma sheath will severely hinder the real-time communication between the ground command center and the aircraft.With the development of computer hardware and computing technology, Particle in cell(PIC) method is widely used in the numerical simulation of plasma.PIC method is based on first principles, and it is different from the usual numerical simulation by using macroscopic equations.PIC method is using the most basic laws of electromagnetism- Maxwell’s equations, and the most basic laws of mechanics- the Lorentz force equation and Newton’s equation of motion, to calculate the trajectories of a large number of particles in plasma, and then get the plasma macroscopic properties by statistical average according to the distribution of particles in the six-dimensional phase space statistical average, obtain macroscopic properties of the plasma. Therefore, the PIC method can be considered as a theoretical experiment, which is suitable for the study of the nature of the physical problem.In this paper, the PIC method is used to study the energy absorption and reflection of the incident electromagnetic wave in the plasma sheath. At first, the basic process of PIC methods of plasma simulation is introduced, including the basic assumptions of PIC method, calculation of electromagnetic field components and the charge and current density in discrete space, particle push method, improvement of PIC simulation method; Secondly give a simplified modeling of the plasma sheath on the aircraft surface, including the setting of simulate region, initial particle distribution, the setting of boundary condition of simulation area; Finally, the impact of the incident electromagnetic wave energy absorption and reflection under different conditions of plasma sheath is given.