95 GHz三次谐波回旋管设计

采用线性理论和非线性理论研究了回旋管谐振腔结构、寄生模式抑制及注波互作用等问题。设计了一支工作在95 GHz的三次谐波回旋管,注波互作用结构采用标准开放式谐振单腔,工作模式为TE64, 采用电压45 kV、电流5 A、横纵速度比为1.5的小回旋电子注。在不考虑电子注速度离散及厚度的情况下,非线性理论分析表明,该回旋管可以获得14 kW功率输出,横向互作用效率约为18%,整管效率约11%。     

170GHz兆瓦级同轴回旋振荡管的分析计算

回旋管是最有希望应用于正在实施的国际热核实验反应堆计划的微波源器件,然而研究设计符合要求的回旋管还存在很多困难需要解决.对170 GHz兆瓦级光滑同轴回旋管的注-波互作用进行了研究.选取模式谱相对稀疏的TE31,12作为工作模式,利用Matlab编制源程序,计算了同轴回旋管的注-波耦合系数、起振电流.在考虑电子速度零散、腔壁电阻率和单模近似的基础上,对光滑同轴谐振腔的优化设计和注-波互作用进行了仿真,给出了磁场、电压、电流和内导体倾角等参量与回旋管效率的关系.结果表明,电压和磁场对回旋管效率影响较大,电子速度零散对回旋管效率影响较小,因而可降低电子枪的设计要求.此外,优化内导体倾角和同轴谐振腔结构参数可提高注-波互作用效率,降低电子速度零散对互作用效率的影响,获得了约50%的电子效率及1.7 MW输出功率.     

双共焦波导结构二次谐波太赫兹回旋管谐振腔设计

准光共焦波导具有功率容量大、模式密度低的特点,能够有效地减少模式竞争对回旋管互作用的影响,有利于高次谐波太赫兹回旋管的设计.为提高太赫兹准光回旋管的互作用效率,在共焦柱面波导的基础上,研究了一种新型高频互作用结构——双共焦波导结构,设计了一种330 GHz二次谐波双共焦结构回旋管谐振腔并对其进行了理论分析和粒子模拟.研究结果表明,双共焦谐振腔中的高阶模式能够与高次电子回旋谐波发生稳定的相互作用,并且没有模式竞争现象,具备工作在太赫兹波段的潜力.相比普通共焦波导谐振腔,双共焦谐振腔能够增强准光回旋管的注波互作用强度,提高回旋管的输出功率和工作效率.此外,结果还表明双共焦波导中的电磁波模式是一种由两个独立的共焦波导模式叠加而成的混合模式.利用这种混合模式有望实现太赫兹回旋管的单注双频工作,为新型太赫兹辐射源的研究提供了新的途径.     

70 GHz二次谐波倍频回旋速调管研究

 对70 GHz二次谐波倍频回旋速调管高频结构和电子与波互作用进行了研究。研究了TE02模腔体绕射品质因数及模式转化，解决了二次谐波倍频回旋速调管漂移段不能截止70 GHz的TE01模而引起的腔体间高频串扰的问题。分析了注电流、输入功率、电子横纵速度比和电子注引导中心半径等参数对输出功率、增益和效率的影响。针对二次谐波回旋速调管放大器工作频带窄、效率低，进行了高频结构优化设计，显著地展宽了工作频带，提高了互作用效率。在理论分析和高频计算的基础上，建立了注-波互作用PIC（粒子模拟）模型，进行了粒子模拟计算和优化，得到了70 GHz 的二次谐波倍频四腔回旋速调管放大器设计方案。粒子模拟结果表明：在工作电压70 kV，注电流13 A，电子注横向速度与纵向速度比为1.5时，中心频率69.81 GHz输出功率256 kW，带宽160 MHz，电子效率28%，饱和增益大于44 dB。     

突变复合腔回旋管自洽场理论与模拟

研究了具有突变结构复合腔回旋管注波互作用自洽非线性理论.用场匹配方法处理了腔中的突变结构,从具有电子流源的普遍传输线方程出发,研究了腔中注波互作用非线性理论,在腔直径渐变部分考虑了模式之间的耦合.利用此非线性理论模型,对突变结构复合腔三次谐波回旋管中电子流与H511—H521模式对的高频场互作用进行了详细数值模拟,得出了许多有价值的结果.计算结果表明,在合适的腔体结构尺寸下,注波互作用效率可大于25%. 关键词：     

94GHz基波复合腔回旋管数值模拟

通过对94 GHz基波复合腔回旋管中谐振腔结构、电子注参数以及注-波互作用过程的模拟计算研究,分析了复合腔回旋管的高频结构特性和工作参数优化问题.给出了基波H61 -H62模式对复合腔回旋管的模拟设计结果.数值模拟结果表明:在电子注电压40 kV、电流5A、电子横纵速度比1.3、工作磁场3.6T时,回旋管可获得78 k...     

全三维110GHz和220GHz同轴腔双注回旋管数值模拟研究

为了打破传统单注回旋管只能产生较低功率的局限性, 本文基于自主研发的PIC粒子模拟软件CHIPIC 对110 GHz和220 GHz同轴腔双注回旋管进行全三维数值模拟研究. 在理论分析同轴双电子注电子枪设计模型和初始参数的基础上通过CHIPIC对其进行优化设计, 得到了具有横纵速度比为1.0, 最大速度零散约为5.4%的高性能电子束; 并将此优化后的双阳极双注电子枪取代传统回旋管数值模拟时采用的回旋 发射进行110 GHz和220 GHz双注回旋管整管的数值模拟, 并采用MPI四进程并行计算, 最终获得了具有双频分别为110 GHz和220 GHz、模式为TE₀₂模、平均输出功率约在70 kW、 效率达到8.75%的高性能双注回旋振荡管. 关键词： 同轴腔双注回旋管 同轴双电子注电子枪 横纵速度比 速度零散     

W波段二次谐波突变复合腔回旋管数值模拟

 通过对二次谐波低电压突变结构复合腔回旋管中谐振腔结构、模式竞争以及电子注-波互作用的研究,分析了高频结构特性、寄生模式的抑制和工作参数优化等问题。给出了3 mm 二次谐波低损耗TE₀₂/TE₀₃模式回旋管的模拟设计结果。计算采用了坡度磁场,互作用效率得到显著提高。PIC粒子模拟结果表明:在电子注电压25 kV、电流4 A、纵横速度比1.6、工作磁场1.72 T时,回旋管可获得37 kW 的输出功率,横向运动能量转换效率高达51%,器件效率为37%。     

TE_(02)模式95 GHz三次谐波回旋管实验

首次实现W波段三次谐波回旋管输出功率突破10kW。谐波回旋管互作用结构采用带有光阑结构的圆柱型开放式谐振腔,工作模式为低损耗圆对称模式TE02。实验中,在脉冲宽度20μs、电子束电压45kV、电流3A、磁场1.23T时,测得工作频率为95.22GHz,输出功率13.4kW,对应效率9.9%。     

3 mm波段回旋速调管放大器设计与粒子模拟

设计了一支3 mm 波段基波回旋速调管,该回旋速调管工作在低损耗的TE01模式,包含四个谐振腔。首先使用线性理论确定工作参数的大致范围, 然后采用HFSS软件设计单个谐振腔,通过调整谐振腔尺寸和腔壁介质层参数使谐振腔的谐振频率和Q值符合设计要求, 最后使用粒子模拟程序优化设计了回旋速调管的互作用电路,研究了谐振腔参差调谐方案, Q值对回旋速调管性能的影响, 互作用电路的稳定性以及电子注参数变化对注-波互作用性能的影响。PIC粒子模拟结果表明,在电子注电压65 kV, 电流6 A, α(V⊥/V∥)1.5, 工作磁场3.6 T时,回旋速调管的3 dB带宽约为600 MHz,在93.7 GHz获得139 kW 的峰值输出功率,效率为35.6%,增益为28.4 dB。模拟中没有考虑电子注速度零散的影响。     

A cavity with reduced mode conversion for gyrotrons

Mode conversion at discontinuities of an ordinary gyrotron cavity is examined. It is shown how the production of unwanted spurious modes can be reduced substantially by introducing smooth transition regions between the individual parts of the cavity. The cavity of the 140 GHz KfK gyrotron operating in the TE_10,4 mode is used as an example. Cavity and adjacent tapered output waveguide are optimized as a single unit.     

94 GHz回旋管过模波导模式转换与传输

 在耦合波理论的基础上,研究了94 GHz回旋管内置TE₀₃-TE₀₂-TE₀₁模式转换器和外接的TE₀₁-TE₁₁模式转换器。采用半径渐变微扰和轴线微扰几何结构以及不同的相位重匹配技术进行优化分析,得到了可靠的最优几何参量,设计出了紧凑、高效的94 GHz波纹波导模式转换器和蛇形线模式转换器。回旋管的热测实验中测出的模式样图表明,所设计的内置模式变换器有效地实现了TE₀₃-TE₀₂-TE₀₁的模式转换。     

Technological gyrotron with low accelerating voltage

We consider the design of a gyrotron with an operating frequency of 24 GHz and an accelerating voltage of about 5 kV and describe a nonadiabatic electron gun forming an electron beam with a pitch factor of 1.8 and a velocity spread of about 10%. Longitudinal distribution of high-frequency field in a cavity with a step is optimized by choosing the step height and length. The design value of the gyrotron output efficiency is 35% at the second gyrofrequency harmonic.     

A High-Efficiency Second-Harmonic Gyrotron with a Depressed Collector

The gyrotron with an electrically insulated collector has been manufactured and tested. The 60% output efficiency is obtained for the Collector Potential Depression (CPD) operation regime. The results of the numerical simulation of the electron energy spectrum in the collector region of the second-harmonic technological 24 GHz gyrotron are presented. It is shown, that the minimal electron beam energy is about 20% of the initial value and that the gyrotron cavity should be expanded to achieve the highest output efficiency of the gyrotron with energy recovery. The highest experimental decelerating voltage is in good agreement with the calculation of the electron energy spectrum.     

28 GHz/50 kW准光输出连续波回旋管

研制出国内首支基于电子回旋加热应用的28 GHz/50 kW准光输出大功率连续波回旋管。该回旋管采用了双阳极磁控注入枪,TE₀₂模式谐振腔,内置准光模式变换器,单级降压收集极。回旋管采用无液氦制冷超导磁体提供稳态磁场。实验中成功实现54.8 kW/1 s短脉冲输出和45.8 kW/30 s的连续波输出,工作频率为28.08 GHz,总效率达到57%。     

A 1.5-MW, 140-GHz, TE28,16-coaxial cavity gyrotron

The design of a 1.5-MW, 140-GHz, TE-_28,16-coaxial cavity gyrotron is presented and results of experimental operation are given. A cavity with a cylindrical outer wall and a radially tapered inner rod with longitudinal corrugations was used. A maximum output power of 1.17 MW has been measured in the design mode with an efficiency of 27.2%. Single-mode operation has been found over a wide range of operating parameters. The experimental values agree well with the results of multimode calculations. Frequency-step tuning has been performed between 115.6 and 164.2 GHz. In particular, an output power of 0.9 MW has ben measured in the TE_25,14 mode at 123.0 GHz and 1.16 MW in the TE_32,18 mode at 158.9 GHz. At frequencies its with strong window reflections the parameter range for which stable operation is possible is reduced significantly. In order to obtain results relevant for a technical realization of a continuously operated gyrotron, a tube with a radial radio frequency (RF)-beam output through two output windows and a single-stage depressed collector has been designed and is under fabrication. A two-step mode conversion scheme-TE- _28,16 to Te_+76.2 to TEM₀₀-which generates two narrowly directed (60° at the launcher) output wavebeams has been chosen for a quasioptical (q,o) mode converter system. A conversion efficiency of 94% is expected     

TE_(02)模式W波段三次谐波回旋管腔体设计

设计了用于W波段三次谐波回旋管的带有iris结构的开放式谐振腔。采用低损耗圆对称模式TE_(02)工作。起振电流为2.9A,欧姆效率67%。PIC数值模拟结果表明,TE_(02)模式在iris谐振腔中可以实现稳定的W波段三次谐波单模振荡。当电压为45kV、电流为4A、横纵速度比为1.5时,可以获得25.7kW功率输出,对应的工作效率为14.3%。     

Theory of step-tunable gyrotrons operating at two cyclotronharmonics

The scaling of operating parameters and the tendencies in the efficiency of the step-tunable gyrotron operating in a set of modes in a cavity of a given length are considered. Results of calculations are reported for the design of a ~1-kW, step-tunable gyrotron oscillator operating from 150 to 600 GHz in steps of about 15 GHz. Detailed results are presented for the efficiency, power losses in the cavity, and the starting conditions. Designs of the electron gun electrodes and of an output mode transducer are also presented. Full modulation of the radiation via the modulating anode of a magnetron injection gun is considered. The gyrotron would be of use for plasma diagnostics and spectroscopy, including electron paramagnetic resonance spectroscopy (EPR)     

Effect of Resonator Parameters on Frequency and Quality Factor of Gyrotron Resonators

The influence of some cavity parameters on the resonance frequency and quality factor is investigated with the aim of comparing various methods of optimization. As an example, the geometry of the designed resonator for an experiment on a multifrequency gyrotron that would operate at 140 GHz in the TE_22,8 mode is considered. This is a weakly–tapered conventional cavity resonator with parabolic–roundings. The influence of the roundings on the quality factor is at least as important as that of the cavity length and the output taper angle.