Attenuation Coefficient Of Electromagnetic Waves In Plasma

The problem of the electromagnetic wave propagation andabsorption in plasma，no matter from the plasma itself or its practical applica tion，is a very active area ofresearch. Such as plasma stealth technology，plasma wave heating technology，etc，which many researchers take interest in and become a hot research topic in the fieldof plasma physics，atmospheric physics，the ionosphere physics，communicationradar，plasma source and plasma antenna，etc.The characteristics of electromagnetic wave propagation and absorption in theatmospheric pressure plasmas layer and mainly consider the influence of positive andnegative ions in atmosphere on the electromagnetic wave absorption performance.In the first chapter，we make a brief introduction to the concept of plasma，plasma parameters， the application of plasma and two kinds of plasma stealthmethod.In the second chapter，plasma is regarded as a system composed of positive andnegative ions，electrons and neutral gas. We study the attenuation phenomenon ofelectromagnetic wave propagation in plasma and the reflection phenomenon in theplasma screen，by calculating the attenuation coefficient and the phas e factor.Especially，we study the influence of the existence of the negative ions in theatmosphere on the electromagnetic wave propagation in plasma. Results show thatcontribution of ions cannot be ignored，when the density of ion is electronic’sseveral times.The properties of electromagnetic wave propagation in a vacuum-plasmas layer-vacuum model are studied in the third chapter. We research the relationships betweenthe power of electromagnetic wave absorption，reflection and transmission with thecoefficient of attenuation and phase.The properties of electromagnetic wave propagation in the plasmas layercovering on the surface of metal and study the relationships between the power ofelectromagnetic wave absorption and reflection with the attenuation coefficient in thefourth chapter. And the method of superposition of multiple beam is firstly used toresearch the reflected power ratio.Then， the reflection power of the powercalculation is compared with the one calculated by the method of superposition ofmultiple beam. We found that the reflected power ratio calculated by the method ofsuperposition of multiple beam can appear tiny shock. And the shock is produced bythe superposition of coherence light rather than the error of the numerical simulation. In the fifth chapter,I use analytical and numerical simulation of the Euler methodto calculate the power reflectivity changes with the frequency of electromagneticwaves, and further analysis of the spatial variation of the amplitude of the electricfie ld intensity with position, and calculates a cycle of the electromagnetic wave in avacuum plasma layer waveform, and use Euler numerical simulations for calculatingthe change in non-uniform plasma with electromagnetic frequency power reflectivity.Numerical simulation results agree well with the analytical results.