Dynamics of the axial mode transition process in a 0.33-THz second-harmonic gyrotron is investigated to reveal the physical mechanism of realizing broadband frequency tuning in an open cavity circuit. A new interactio...Dynamics of the axial mode transition process in a 0.33-THz second-harmonic gyrotron is investigated to reveal the physical mechanism of realizing broadband frequency tuning in an open cavity circuit. A new interaction mechanism about propagating waves, featured by wave competition and wave cooperation, is presented and provides a new insight into the beam-wave interaction. The two different features revealed in the two different operation regions of low-order axial modes （LOAMs） and high-order axial modes （HOAMs） respectively determine the characteristic of the overall performance of the device essentially. The device performance is obtained by the simulation based on the time-domain nonlinear theory and shows that using a 12-kV/150-mA electron beam and TE 3,4 mode, the second harmonic gyrotron can generate terahertz radiations with frequency-tuning ranges of about 0.85 GHz and 0.60 GHz via magnetic field and beam voltage tuning, respectively. Additionally, some non-stationary phenomena in the mode startup process are also analyzed. The investiga- tion in this paper presents guidance for future developing high-performance frequency-tunable gyrotrons toward terahertz applications.展开更多
Gyrotrons are high powered coherent electromagnetic radiation sources, and are considered to be available powerful sources that have the potential to bridge the so-called terahertz gap. In the University of Electronic...Gyrotrons are high powered coherent electromagnetic radiation sources, and are considered to be available powerful sources that have the potential to bridge the so-called terahertz gap. In the University of Electronic Science and Technology of China, a second harmonic gyrotron has been designed, manufactured, and tested. The gyrotron generated radiation at a 0.423 THz frequency in 5μs pulses with an 8.1 Tesla magnetic field, with a power per pulse of about 4.4 kW. To date this is the highest frequency recorded for vacuum electronic devices in China. The gyrotron design, operation and measurements are presented.展开更多
为面向前沿科学研究,介绍了WHMFC(Wuhan National High Magnetic Field Center)基于自研软件开发的太赫兹谐波回旋管平台,简述了平台的设计方案及实验系统。该平台已利用15 T超导磁体开展一系列相关实验,实现了二次谐波下TE 8,5模式、...为面向前沿科学研究,介绍了WHMFC(Wuhan National High Magnetic Field Center)基于自研软件开发的太赫兹谐波回旋管平台,简述了平台的设计方案及实验系统。该平台已利用15 T超导磁体开展一系列相关实验,实现了二次谐波下TE 8,5模式、基波下TE 1,4、TE 3,3等多种模式的输出与频率、功率测量,在14.81 T磁场下,测量得到了约800 GHz的谐波辐射。进一步放宽磁场调节范围,测量到了工作在不同TE模式下的基波,频率涵盖了从217 GHz到381 GHz的较宽范围,功率达数十瓦到数百瓦不等。初步实验结果表明,所开发的回旋管平台在基波、谐波工作方式下均具有良好的输出能力。展开更多
采用谐波工作的回旋管互作用磁场比基波磁场降低了1/s,可降低整管磁场设计难度,具有较大的应用前景。通过对W波段二次谐波回旋行波管高频介质加载结构、模式竞争和注波互作用研究,确定了该放大器的工作参数。非线性模拟表明,当应用100 k...采用谐波工作的回旋管互作用磁场比基波磁场降低了1/s,可降低整管磁场设计难度,具有较大的应用前景。通过对W波段二次谐波回旋行波管高频介质加载结构、模式竞争和注波互作用研究,确定了该放大器的工作参数。非线性模拟表明,当应用100 k V,20 A,α=1.2的电子注时,该回旋管可在91 GHz频率处产生465 k W的输出功率和49 d B的增益结果。并且,基于耦合波理论,讨论了一个轴对称半径微扰的TE02~TE01输出模式变换器,效率在95%以上时,其带宽达到4 GHz。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61471007,61531002,61522101,and 11275206)the Seeding Grant for Medicine and Information Science of Peking University,China(Grant No.2014-MI-01)
文摘Dynamics of the axial mode transition process in a 0.33-THz second-harmonic gyrotron is investigated to reveal the physical mechanism of realizing broadband frequency tuning in an open cavity circuit. A new interaction mechanism about propagating waves, featured by wave competition and wave cooperation, is presented and provides a new insight into the beam-wave interaction. The two different features revealed in the two different operation regions of low-order axial modes （LOAMs） and high-order axial modes （HOAMs） respectively determine the characteristic of the overall performance of the device essentially. The device performance is obtained by the simulation based on the time-domain nonlinear theory and shows that using a 12-kV/150-mA electron beam and TE 3,4 mode, the second harmonic gyrotron can generate terahertz radiations with frequency-tuning ranges of about 0.85 GHz and 0.60 GHz via magnetic field and beam voltage tuning, respectively. Additionally, some non-stationary phenomena in the mode startup process are also analyzed. The investiga- tion in this paper presents guidance for future developing high-performance frequency-tunable gyrotrons toward terahertz applications.
基金supported by the National Natural Science Foundation of China (60877058)the National Basic Research Program of China (2007BC310401)
文摘Gyrotrons are high powered coherent electromagnetic radiation sources, and are considered to be available powerful sources that have the potential to bridge the so-called terahertz gap. In the University of Electronic Science and Technology of China, a second harmonic gyrotron has been designed, manufactured, and tested. The gyrotron generated radiation at a 0.423 THz frequency in 5μs pulses with an 8.1 Tesla magnetic field, with a power per pulse of about 4.4 kW. To date this is the highest frequency recorded for vacuum electronic devices in China. The gyrotron design, operation and measurements are presented.
文摘为面向前沿科学研究,介绍了WHMFC(Wuhan National High Magnetic Field Center)基于自研软件开发的太赫兹谐波回旋管平台,简述了平台的设计方案及实验系统。该平台已利用15 T超导磁体开展一系列相关实验,实现了二次谐波下TE 8,5模式、基波下TE 1,4、TE 3,3等多种模式的输出与频率、功率测量,在14.81 T磁场下,测量得到了约800 GHz的谐波辐射。进一步放宽磁场调节范围,测量到了工作在不同TE模式下的基波,频率涵盖了从217 GHz到381 GHz的较宽范围,功率达数十瓦到数百瓦不等。初步实验结果表明,所开发的回旋管平台在基波、谐波工作方式下均具有良好的输出能力。
文摘采用谐波工作的回旋管互作用磁场比基波磁场降低了1/s,可降低整管磁场设计难度,具有较大的应用前景。通过对W波段二次谐波回旋行波管高频介质加载结构、模式竞争和注波互作用研究,确定了该放大器的工作参数。非线性模拟表明,当应用100 k V,20 A,α=1.2的电子注时,该回旋管可在91 GHz频率处产生465 k W的输出功率和49 d B的增益结果。并且,基于耦合波理论,讨论了一个轴对称半径微扰的TE02~TE01输出模式变换器,效率在95%以上时,其带宽达到4 GHz。
