Numerical Simulation Of High Frequency Electromagnetic Wave Propagation In Weakly Ionized Plasma

The propagation of electromagnetic wave in plasma is a sophisticated investigation field. In recent years, it attracts more attention because of its potential applications in plasma stealth, electromagnetic protection,electromagnetic countermeasure and space communication. In this thesis, high frequency electromagnetic wave propagating in weakly ionized collisional plasma is studied using a numerical model. The model includes the Maxwell’s equations and the plas-ma fluid equations which are solved by FDTD method, to describe the propagation process.We focus on the effect of some typical parameters on the electromagnetic wave propagation.Firstly, we study the case that electromagnetic wave normal incidence into plasma.As we known, plasma has high-pass filtering character to the electromagnetic wave, however high co-llision frequency can reduce this character and put a lower cutoff frequency which is the plasm-a frequency originally. Different optimal collision frequencies correspond to different electro-magnetic wave frequencies. Collisional absorption is the main reason of electromagnetic wave being attenuated in plasma. Since the highest electron density in an parabolic inhomogeneous plasma leads to a highest plasma frequency, we find that a kind of resonance absorption, which is quite different from the collisional absorption, occurs when the electromagnetic frequency is close to the highest frequency.Secondly, electromagnetic wave which is oblique-incidence into plasma has been studied. For transverse magnetic wave (TM wave), the larger oblique incidence angle leads to the more reflection in atmosphere-plasma interface, and make more absorption for those TM wave imm-ersed plasma. For transverse electric wave (TE wave), when oblique incidence angle is nearby30°, a smallest reflection appears in atmosphere-plasma interface, and the immersed TE wave has a strong absorption which behaviors similar with TM wave. From simulation,we find an op-timum electron density exists under particular oblique incidence angle.Finally, electromagnetic wave propagating in magnetized plasma has been investigated for two cases. When the external magnetic field is parallel to the electromagnetic wave vector, electron cyclotron resonance occurs in a collisionless plasma, in the case that electromagnetic wave frequency is close to the electron cyclotron resonance frequency. The resonance freque-ncy changes with the strength of the external magnetic field. When the external magnetic field is perpendicular to the electromagnetic wave vector, electromagnetic wave have an upper hy-brid resonance in both collisionless and collision plasma, in the case that the electromagnetic wave frequency is close to the upper hybrid resonance frequency. The resonance frequency is effected by both of the external magnetic field strength and the electron density.