新式開口式共振腔之能流分析

Abstract

開口式共振腔之研究常應用於磁旋管、磁旋振盪管中，與閉口式共振腔不同的是其有明確的邊界條件，因此我們運用程式做數值模擬其解析解來探討其不同的物理意義。先前的研究主要有兩種，一是在時域下，分析基本結構或是改變不同的共振腔結構（加入不匹配負載結構）、材料性質後，解析及探討不同的品質因子以及共振頻率的關係；二是在頻域下，注入不同頻率的電磁波後，看其反射係數與其注入頻率的關係。 本論文主要結果是發展自先前的基礎研究，在時域基礎模型中，定義電動力學中的Poynting vector在一個週期中的z方向上平均值為開口式共振腔功率流的淨值P_net，也改變共振腔的結構及材料性質，運用數值模擬分析電磁波能流大小在數值上受複數影響的樣態，並在文中給予合理的物理解釋及探討。

Researches of Open Cavities are commonly used in gyrotrons and gyromonotron oscillators. Different from the enclosed cavities, it has well-defined geometrical boundary conditions. There are mainly two kinds in previous researches. One is under Time-Domain, analyzing and discussing the relation of different quality factor Q and resonant frequency with the basic structure or changing the structure or the material of the cavities. The other is under Frequency-Domain, injecting electromagnetic waves with different frequency. Then, observe and discuss the relation of coefficient and the injected frequency. The main result of this thesis is developed from the previous researches of Time-Domain. Basic from the knowledges of Electrodynamics, we denote the average value of the Poynting vector in the z-direction among a period as the net wave power flowing. Also, changing the structure, analyze the power flow of the wave with numerical simulations. Lastly, we give reasonable physical explanations in this thesis.