Study On The Propagation Characteristics Of Electromagnetic Wave In High Temperature Plasma

When the aircraft enters the atmosphere at a super high speed,it will friction with the surrounding air to generate a high-temperature plasma sheath.The existence of the plasma sheath will seriously affect the propagation of electromagnetic waves and even cause the interruption of communication signals.The existence of "blackout" in communication not only interrupts the signal,but also threatens the life of the pilot.It is impossible to obtain the flight conditions of the aircraft.With the development and application of terahertz wave technology,a new method is provided for solving the problem of communication interruption.In this paper,the electromagnetic wave in the terahertz band is selected as the communication carrier.It is studied the influence of high temperature plasma on the transmission characteristics of the terahertz wave.The main research contents are as follows:Firstly,the electromagnetic wave theory and plasma physics are studied.For practical applications,the main models of plasma research,the half-space infinite plasma model,the uniform sharp boundary plasma model,the non-uniform sharp boundary plasma model and the constrained plasma model are analyzed for the characteristics of electromagnetic wave propagation.It is proposed an improved air-high temperature plasma-air transport model based on the original.Different calculation methods are adopted for different models.Numerical analysis method is the main calculation method in this paper to study the interaction between plasma and electromagnetic waves.Secondly,this paper mainly studied the propagation characteristics of electromagnetic waves in high temperature magnetization and homogeneous plasma.The changes of electromagnetic density(eN),plasma collision frequency(env),plasma thickness(d)and magnetic induction intensity(B)with high temperature plasma are analyzed theoretically.In addition,the physical model and numerical calculation of electromagnetic wave perpendicular incidence well be established.With the help of the simulation results are obtained by programming,the experimental results show that the attenuation value does not change linearly with the increase of the terahertz frequency,the attenuation increases with the increase of the electron density,and the attenuation cannot be reduced with the increase of the collision frequency.The attenuation peaksmove in the high-frequency direction of the incident wave.Finally,the transmission characteristics of non-magnetized and uniform plasma at high temperature are studied in this paper.The oblique incidence high temperature plasma transmission model of electromagnetic wave is established and theoretical analysis is performed.The reflection,transmission and attenuation of electromagnetic waves under different parameters of high temperature plasma were studied.Numerical results show that temperature factors can cause changes in electromagnetic wave characteristics,and high-temperature plasmas have zero and negative absorption of terahertz waves.In summary,the variation law of electromagnetic wave transmission in high-temperature plasma is studied in this paper.The range of parameters such as collision frequency,temperature and magnetic field intensity is obtained to alleviate the black barrier phenomenon.Therefore,using terahertz waves as communication carriers under appropriate parameters can greatly improve communication efficiency.