PPLT倍频宽线宽掺镱双包层光纤放大激光

分别通过理论和实验研究了周期性极化的钽酸锂（PPLT）倍频宽线宽准连续掺镱双包层光纤放大激光.PPLT样品长为40 mm,极化周期为7.67 μm.基频光的中心波长为1064 nm,线宽约为6 nm.从基频光的光谱特性出发,利用超晶格倍频理论,解释了实验中获得的倍频温度与二次谐波功率之间的关系.在基频光的功率为2.2 W时,获得的宽线宽光纤激光倍频效率为1.8%.     

回旋速调管注-波互作用非线性理论研究

 利用自洽非线性理论对回旋速调管放大器中的电子注-波互作用进行了时域瞬态分析,建立了多腔回旋速调管非线性理论,给出了相应的电子运动方程和复数形式的互作用瞬态场方程。给出并分析了一支工作在TE01模Ka波段四腔回旋速调管注-波互作用的数值计算结果,当电子注电压为72.8 kV,电流为11.8 A,速度零散为5%时,可以得到335 kW的最大饱和功率输出,39.6%的电子效率及320 MHz的饱和带宽,与实验值相比较,二者较为吻合。     

Calculation of the Electron Efficiency for a Two-Cavity Gyroklystron Amplifier by Using a Self-Consistent Code

The beam-wave interaction in a Ka-band, two-cavity fundamental gyroklystron amplifier is studied by using a self-consistent nonlinear simulation code. The electron efficiency for this gyroklystron amplifier is calculated, and the effect of various parameters, such as beam voltage, beam current, electron guiding center radius, velocity pitch ratio and drift tube length on the electron efficiency is discussed in detail.     

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。     

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。     

Novel Applications of Millimeter and Submillimeter Wave Gyro-Devices

The possible applications of high-power millimeter (mm) and submillimeter waves from gyro-devices span a wide range of technologies. The plasma physics community has already taken advantage of recent advances in applying high-power micro- and mm-waves generated by gyrotron oscillators in the areas of RF-plasma production, heating, noninductive current drive, plasma stabilization and active plasma diagnostics for magnetic confinement thermonuclear fusion research, such as lower hybrid current drive (8 GHz), electron cyclotron resonance heating (ECRH) (28–170 GHz), electron cyclotron current drive (ECCD), collective Thomson scattering and heat-wave propagation experiments. Other important applications of gyrotrons are electron cyclotron resonance (ECR) discharges for generation of multi-charged ions and soft X-rays, as well as industrial materials processing and plasma chemistry. Submillimeter wave gyrotrons are employed in high-frequency broadband electron paramagnetic resonance (EPR) spectroscopy. Future applications which await the development of novel high-power gyro-amplifiers include high resolution radar ranging and imaging in atmospheric and planetary science as well as deep-space and specialized satellite communications and RF drivers for next-generation high-gradient linear accelerators (supercolliders). The present paper reviews the state-of-the-art and future prospects of these recent applications of gyro-devices.     

Analyses of two-cavity gyroklystron with feedback

Making use of the linear kinetic theory and the perturbation approach, a gyroklystron with feedback, in which a low order (TE₀₁₁) mode is presented in the bunching cavity by the feedback of the output cavity, and the low order mode in the bunching cavity is coupled by the electron beam to a high order (TE₀₂₁) mode in the output cavity, has been investigated in detail. And electron beam to wave interaction in each cavity and electron bunching mechanism in the bunching cavity have been analysed. The formulas of electron beam to wave interaction power and starting current etc. have been derived. Then some calculations are carried out.     

阴离子表面活性剂-健那绿体系的二级散射光谱及其分析应用

建立了二级散射光谱法测定阴离子表面活性剂的新方法。研究了阴离子表面活性剂SDBS与健那绿离子缔合物的二级散射和"反二级散射"光谱。结果表明:当λem=340nm,λex=680nm时,在0～50μg mL质量浓度范围内,ΔIFDS与溶液中物质的质量浓度成正比,线性相关系数为0.9988,检出限为17.4ng mL。     

Self-consistent nonlinear analysis of a frequency-quadrupling terahertz gyroklystron

This paper analyses a three-cavity frequency-quadrupling terahertz gyroklystron with successive frequency-doubling in each cavity with self-consistent nonlinear theory. The beam--wave interaction efficiency and the electron bunching process are studied. The variation of output efficiency with the length of drift tubes and output power and the variation of Ohmic loss with the length of output cavity are considered. Numerical simulations predict an optimal output efficiency of 1.8%, a power output of more than 2~kW and a gain of 33~dB after taking into account Ohmic losses when the frequency-quadrupling gyroklystron, driven by a 40-kV, 3-A electron beam and 1 Watt input power, operates at 225~GHz.     

回旋速调管放大器时域非线性理论与模拟

研究了一种回旋速调管放大器时域非线性理论模型.该模型由广义电报方程来表示回旋速调管内的电磁场,采用引导中心近似的电子运动方程来推动粒子,由粒子更新得到的电流密度为源激励电磁场.基于上述理论模型,从回旋速调管电子注横向速度满足高斯分布出发,建立了速度分散的分布模型,编写了相应的时域非线性注波互作用模拟程序,对回旋速调管放大器的注波互作用进行了深入的分析和研究,并应用粒子模拟软件与自洽非线性模拟程序进行对比验证,两者结果基本一致.