Effects Of Plasma Parameters On Gigahertz Electromagnetic Wave Power Absorption

The absorption,reflection and refraction of electromagnetic waves by plasma is a very important physical problem,which has been widely studied in various fields.An analytical,adjustable gradient parameters density distribution function is presented to describe electron density profiles of different bell-like shapes.Based on the given electron density profile and for the gigahertz electromagnetic waves in the frequency ranges from 0.20 GHz to 30 GHz,the effects of thickness of the non-uniform plasma layer,the plasma collision frequency,the electron density and other parameters on the power absorption during electromagnetic wave propagating in the cold plasma are investigated and compared with the corresponding results in a uniform cold plasma layer by using WKB(Wentzel-Kramers-Brillouin)method.The optimal parameters are given to control and enhance the absorption of gigahertz electromagnetic waves in the mid-low frequency band.On this basis,an asymmetric density gradient profile is designed to obtain a higher absorption rate and a wider absorption band than the symmetric electron density profile.The first chapter briefly introduces the research background of plasma stealth technology,the concept and classification of plasma,the main physical properties of plasma as electromagnetic wave propagation medium,the basic principles and research methods of plasma stealth technology,etc.In chapter two,the analytical electron density distribution function is given,and the WKB method is used to calculate the power absorption,power reflection and power transmission of non-magnetized gigahertz electromagnetic wave propagating in uniform and non-uniform cold plasma.In the third chapter,the relationship between the power absorption,power reflection,power transmission and plasma parameters,the effect of electron density gradient on power absorption and its absorption mechanism.In this paper,an asymmetric electron density distribution profile is designed which is beneficial to broaden the absorption band and improve the absorption rate.The fourth chapter studies the propagation characteristics of gigahertz electromagnetic wave in cold plasma with the asymmetric electron density distribution,and compares it with the case of symmetric electron density distribution.The results are compared with the cases of symmetric electron density distribution.The relationship between plasma parameters and absorption peaks when gigahertz electromagnetic waves propagate in asymmetric cold plasmas is mainly studied.The results show that the absorption peak can be moved from the low frequency band to the high frequency band by selecting asymmetric electron density distribution and increasing the center electron density in the selected parameter range.The fifth chapter summarizes the main achievements in this paper,lists the innovations and gives the prospect of future work.