磁旋行波放大器是藉由電子迴旋的都卜勒頻移而使電子束能量轉換成電磁波的毫米波放大器，而由於TE01模式磁旋行波放大器具有低歐姆損耗及高迴旋中心半徑兩種特性，有利於產生高功率毫米波，然而受限於磁旋行波放大器可能引發自發振盪及反射振盪，造成模式競爭而抑制原先操作模式的放大波，進而影響其輸出功率、增益及效率。模擬結果顯示，TE02、TE01模式絕對不穩定的引發使得原有操作電流降低，其起振電流明顯受電子速率比、作用段長度的影響，但此模式可藉由損耗來抑制，此結論與線性理論結果一致。然而另一種TM01模式自發性振盪，其起振電流不僅受電子速率比、作用段長度的影響，且不易藉由損耗來抑制。本研究也針對Ka頻段磁旋行波放大器(NRL)、Ka頻段具有隔離管磁旋行波放大器(UCLA)和W頻段具散佈式損耗磁旋行波放大器(UCD)，藉由電漿模擬程式(MAGIC CODE)進行分析，結果顯示Ka頻段磁旋行波放大器(NRL)其輸入功率需達10KW才能達成放大效果。Ka頻段具有隔離管磁旋行波放大器(UCLA)與W頻段具散佈式損耗磁旋行波放大器(UCD)的模擬結果顯示，由於TE02、TE01和TM01模式振盪而造成輸出功率明顯下降。

The gyrotron traveling wave amplifier (gyro-TWT) is a high-power, broadband, millimeter-wave amplifier. The mode exhibits the lowest ohmic dissipation in previous gyro-TWT experiment. Moreover, it’s field peaks at a radial position of half the waveguide radius, so the quality of electron beam isn’t degraded. Therefore, the TE01 mode gyro-TWT may be a high-power millimeter-wave amplifier. However, the output power, gain, and efficiency of gyro-TWT will be degraded where the spontaneous and reflective oscillations occur. Start-oscillation current will be down by absolute instability of TE02 and TE01 modes and electron velocity ratio and interaction section, it can be suppressed by the distributed wall losses. However, the spontaneous oscillation(TM01 mode) is not effectively suppressed by the distributed wall losses. The Ka band gyro-TWT(NRL) will be amplified, where the input power is 10KW. The output power is decreased because of competition from the TE02、TE01 and TM01 oscillations in the Ka band gyro-TWT(UCLA) with sever and the W band gyro-TWT(UCD) with distributed wall losses.

中文摘要…………………………………………………………..…….…v
英文摘要……………………………………………………………….….vi
致謝…………………………………………………………………….…vii
目錄………………………………………………………………………viii
圖目錄………………………………………………………………………x
第一章 緒論………………………………………………………………1
第二章 研究方法……………………………………………………….12
2.1 線性理論……………………………………………………………12
2.2 非線性理論…………………………………………………………17
2.3 電漿模擬程式…………………………..…………………………17
2.4 MAGIC程式適用性評估…………………………………………..20
第三章　絕對不穩定性………………………………………………….24
3.1 基本原理…………………………………………………………24
3.2 無損耗結構………………………………………………………29
3.3 具損耗結構………………………………………………………35
第四章 磁旋返波振盪……………………………………………….45
4.1 基本原理……………………….0……………………………….45
4.2 起振長度分析……………………………………………………46
第五章 TM01模式的自發性振盪……………………………………48
第六章 TE01模式磁旋行波放大器…………………………………55
6.1 Ka頻段磁旋行波放大器(NRL)…………………………55
6.2 Ka頻段具隔離管磁旋行波放大器(UCLA)…………….60
6.3 W頻段具散佈式損耗磁旋行波放大器(UCD)…………60
結論………………………………………………………………….67
參考文獻…………………………………………………………….68

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