共查询到20条相似文献,搜索用时 15 毫秒
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A cold and uniform plasma-filled travelling wave tube with
sinusoidally corrugated slow wave structure is driven by a finite
thick annular intense relativistic electron beam with the entire
system immersed in a strong longitudinal magnetic field. By means of
the linear field theory, the dispersion relation for the relativistic
travelling wave tube (RTWT) is derived. By numerical computation, the
dispersion characteristics of the RTWT are analysed in different
cases of various geometric parameters of the slow wave structure and
plasma densities. Also the gain versus frequency for three different
plasma densities and the peak gain of the tube versus plasma density
are analysed. Some useful results are obtained on the basis of the
discussion. 相似文献
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Willingale L Nilson PM Thomas AG Cobble J Craxton RS Maksimchuk A Norreys PA Sangster TC Scott RH Stoeckl C Zulick C Krushelnick K 《Physical review letters》2011,106(10):105002
Experiments were performed using the Omega EP laser, operating at 740 J of energy in 8 ps (90 TW), which provides extreme conditions relevant to fast ignition studies. A carbon and hydrogen plasma plume was used as the underdense target and the interaction of the laser pulse propagating and channeling through the plasma was imaged using proton radiography. The early time expansion, channel evolution, filamentation, and self-correction of the channel was measured on a single shot via this method. A channel wall modulation was observed and attributed to surface waves. After around 50 ps, the channel had evolved to show bubblelike structures, which may be due to postsoliton remnants. 相似文献
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射频强度调制激光作为激光雷达系统的载波可以有效提高系统的抗干扰和抗散射能力,高功率宽带射频强度调制光源是实现高分辨率远距离探测的关键.本文采用在Nd:YAG激光器的耦合腔中插入一对四分之一波片的方法实现了频差调谐范围为30 MHz—1.5 GHz的双频激光输出,结合光纤振荡功率放大技术,将双频信号光功率放大为50 W.耦合腔双频种子源具有良好的功率和频率稳定性,输出功率为9.5 mW时,功率标准差为0.145 mW,稳定性为1.52%,输出双频激光的频差为250 MHz时,拍频的标准差为1.6144 MHz.种子光进行三级光纤功率放大,得到50 W双频激光输出.放大后的双频激光功率波动范围小于0.1 W,双频拍频的标准差为1.777 MHz,很好地保持了放大之前的功率稳定性和双频频差稳定性. 相似文献
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A new type of discharge tube for high-power argon-ion lasers constructed of a segmented metal-ceramic compound system is described.
Up to date, the system has been operating for 1500 h without failure. The maximum cw output is 140 W, limited by the destruction
of the mirrors. 相似文献
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为了解决目前3 mm回旋行波管所使用的蓝宝石输出窗因功率容量不足而发生破裂的问题。从抗热震性和功率容量两个方面出发,对常用的几种窗片材料进行了对比。在国内首次以微波等离子体化学气相沉积金刚石为窗片材料,利用数值计算及ANSYS软件仿真设计了用于3 mm回旋行波管的低反射,低吸收,宽带宽,高功率容量的输出窗。结果表明,所设计的输出窗适用于TE01模式输出,其S11参数小于-20 dB的带宽为6 GHz。同时,该输出窗具有良好的抗热震性,在自然对流散热条件下具有61 kW的功率容量。; 相似文献
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Schamiloglu E. Jordan R. Haworth M.D. Moreland L.D. Pegel I.V. Roitman A.M. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1996,24(1):6-7
Open-shutter photography was used to capture the air breakdown pattern induced by a TM01 mode radiated by a high-power backward wave oscillator. The resultant plasma ring was formed in air adjacent to a conical horn antenna fitted with a membrane to keep the experiment under vacuum. This image was digitized and further processed using Khoros 2.0 software to obtain the dimensions of the plasma ring. This information was used in an air breakdown analysis to estimate the radiated power, and agrees within 10% with the power measured using field mapping with an open-ended WR-90 waveguide 相似文献
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An attempt is made to create an electric-discharge source for pumping argon, krypton, and xenon dimer lasers. The device is
based on a method proposed previously by the authors, wherein confinement of the discharge is achieved by removing the cathode
spot from the main discharge region and closing the discharge to the spot along a narrow extended auxiliary plasma channel.
The conditions for the formation of such a discharge are investigated. The high stability of the sparkless stage of the discharge
permits the first-ever attainment of energy depositions at the level of 100 J/cm2 at pressures ∼10 atm, a level several orders of magnitude higher than is attainable by conventional methods. A discharge
cell and power supply system are designed for a multisectional discharge with an active length of 200 mm, and the reliability
of the entire apparatus is demonstrated in long-term use.
Zh. Tekh. Fiz. 67, 10–14 (November 1997) 相似文献
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在传统行波管的放大过程中,随着电子纵向群聚的加深,由于空间电荷效应导致的非线性效应,影响了行波管的输出性能。介绍了一种新型的行波管并分析了其作用机理,分析了这种新型行波管慢波系统的结构及其色散特性,讨论了T形齿结构和梯形齿结构慢波系统几何尺寸对工作性能的影响。通过圆极化行波的高频横向电场调制电子束,导致电子束在空间的扭转,使得电子在放大过程中没有经过纵向群聚而处于减速场中,消除了非线性效应,提高了行波管的输出性能。 相似文献
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A wavelength-tunable,efficient,and high-average power single diode-pumped continuons wave(CW) Yb:SSO laser is reported.A maximum output power of 8.8 W at 1 062.6 nm is obtained using the absorbed pump power of 11.7 W,which corresponds to a slope efficiency of 85.5% and an optical-to-optical conversion efficiency of 48.9%.The wavelength tuning of the Yb:SSO laser pumped by the 976-nm LD is also investigated.The results show the tuning range from 1 002.30 to 1 068.47 nm,which corresponds to a tunability range of 66.17 nm. 相似文献
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《中国物理 B》2015,(9)
By investigating the interaction of an n-type silicon sample with the TM01 mode millimeter wave in a circular waveguide, a viable high-power TM01 millimeter wave sensor is proposed. Based on the hot electron effect, the silicon sample serving as a sensing element(SE) and appropriately mounted on the inner wall of the circular waveguide is devoted to the on-line measurement of a high-power millimeter wave pulse. A three-dimensional parallel finite-difference time-domain method is applied to simulate the wave propagation within the measuring structure. The transverse electric field distribution, the dependences of the frequency response of the voltage standing-wave ratio(VSWR) in the circular waveguide, and the average electric field amplitude within the SE on the electrophysical parameters of the SE are calculated and analyzed in the frequency range of 300–400 GHz. As a result, the optimal dimensions and specific resistance of the SE are obtained,which provide a VSWR of no more than 2.0, a relative sensitivity around 0.0046 kW-1 fluctuating within ±17.3%, and a maximum enduring power of about 4.3 MW. 相似文献
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A cw Pr(3+):LiYF(4) laser at 639 nm pumped by a high-power GaN laser diode (444 nm) is demonstrated. The highest laser power of 112 mW is achieved with an optical-optical conversion efficiency of 33.5%. Characteristics of this laser at elevated temperatures are also investigated for practical applications such as a laser projector. 相似文献
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Kuang E. Davis T.J. Ivers J.D. Kerslick G. Nation J.A. Schachter L. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1994,22(5):511-517
We report experimental and theoretical results from research into high power X-band traveling wave tube amplifiers designed to eliminate sidebands caused by reflections from the output of such structures. These amplifiers have a low energy velocity, such that the time it takes a wave to be reflected from the output to the input is of the order of, or greater than, the electron beam pulse duration. The elimination of sidebands and the effects of reflections is achieved by this transit time isolation, The bandwidth of the output spectrum is limited by the low pass-band of the periodic structures. Such amplifiers have been operated at power levels of up to 160 MW at 9 GHz for 50 ns pulse durations 相似文献
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分布式介质加载技术已被成功应用于回旋行波管的高频结构,该结构对于回旋行波管的自激振荡起到很好的抑制作用。对采用分布式介质加载的Ka波段,工作模式为TE01模的回旋行波管进行了稳定性分析;计算了介质加载条件下工作和寄生模式的传播损耗,以及不同传播损耗下工作模式的起振电流;对不同介质加载条件和工作电流,给出了三个主要寄生模式的起振长度;在对介质加载回旋行波管工作和寄生模式稳定性综合分析的基础上,确定了介质加载厚度及相对介电常数等参数。利用优化设计的高频结构及介质加载参数,进行了整管热测实验,得到了输出功率160 kW,饱和增益40 dB,效率22.8%及3 dB带宽5%的回旋行波管。 相似文献
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分布式介质加载技术已被成功应用于回旋行波管的高频结构,该结构对于回旋行波管的自激振荡起到很好的抑制作用。对采用分布式介质加载的Ka波段,工作模式为TE01模的回旋行波管进行了稳定性分析;计算了介质加载条件下工作和寄生模式的传播损耗,以及不同传播损耗下工作模式的起振电流;对不同介质加载条件和工作电流,给出了三个主要寄生模式的起振长度;在对介质加载回旋行波管工作和寄生模式稳定性综合分析的基础上,确定了介质加载厚度及相对介电常数等参数。利用优化设计的高频结构及介质加载参数,进行了整管热测实验,得到了输出功率160 kW,饱和增益40 dB,效率22.8%及3 dB带宽5%的回旋行波管。 相似文献
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The conditions for the existence of low-frequency electrostatic drift wave in pair-ion plasma are discussed. It is shown that the temperature and/or mass difference of both species could produce drift wave in a pair-ion plasma. The results are discussed in the context of the fullerene pair-ion plasma experiment. 相似文献
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Bernard H Duane 《Annals of Physics》1976,98(1):198-224
The nonlinearly coupled Vlasov-Maxwell ion-plasma field equations are solved exactly for a transversely uniform subgroup of rotational modes induced by a uniform axial magnetic field. The ion orbits in momentum space are bipolar doubly periodic eigenfunctions of ion proper time, obtained in closed form as the difference between two doubly quasi-periodic Weierstrass zeta functions. The ion orbits in position space are helical-spiral doubly quasi-periodic functions of ion proper time, expressible simply in terms of doubly quasi-periodic Weierstrass sigma functions. The complete ion distributions are flexible functions of six constants of the ion motion: wave-frame ion energy, transverse gyro center, an inner Hamiltonian correlating wave-frame ion momentum with wave-frame axial position, and both first and second axial integration constants. A rotary electromagnetic plane wave propagates along the axial magnetic field with complex cisoidal dependence upon wave-frame axial position. The eigenvalue determination intricately interrelates the wave propagation vector, the wave amplitude, the axial magnetic field, the double periods, and the bipole separation. 相似文献