共查询到20条相似文献,搜索用时 109 毫秒
1.
采用小信号理论,在考虑到透射、反射束电子不同作用下,分析了虚阴极振荡器产生微波的机制,获得了计算微波主频的方法,讨论了增强束波作用效率的方法,并提出一种新型结构的虚阴极振荡器。该振荡器的阳极后放置了一个谐振腔,谐振腔长度很小,虚阴极不能在其中形成,谐振腔受到反射电子束激励并建立强场,场对入射电子进行调制,同时采用同轴结构引出微波。利用2.5D PIC 程序对新型的结构进行了数值模拟,验证了理论分析的正确性。在入射电子束电子能量为520keV和电子束流12.5kA的条件下,获得微波平均功率为1GW,频率为3.66GHz,平均束波转换效率为15.3%。 相似文献
2.
3.
对一种阶跃波导虚阴极振荡器进行了数值模拟研究。结果表明阶跃波导长度对高功率微波的产生具有较大的影响;阶跃波导的等效圆柱腔谐振频率与阶跃波导长度和半径有关,当其接近二极管的本征振荡频率时,可以获得比较单一的微波频谱和效率较高的微波输出;微波产生效率随阶跃波导长度呈周期性变化。 相似文献
4.
5.
R. A. Filatov A. A. Koronovskii S. A. Kurkin A. E. Hramov 《Bulletin of the Russian Academy of Sciences: Physics》2012,76(12):1336-1338
The physical processes in a vircator without an external magnetic field and with a drift space filled by neutral gas are studied. Three typical dynamic regimes are found: (1) the suppression of virtual cathode oscillations, (2) pulse generation, in which the suppression and resumption of virtual cathode oscillations are observed, and (3) continuous virtual cathode generation. The frequency dynamics of the vircator’s output radiation is investigated for the last case, and it is shown that the generation frequency of the vircator can rise when the gas pressure exceeds a certain critical value. 相似文献
6.
Analysis of 90° pulsed magnetization signals of ferrite-garnet films with easy plane-type anisotropy
O. S. Kolotov A. V. Matyunin P. A. Polyakov 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(10):1469-1470
The results from a numerical analysis of 90° pulsed magnetization signals of ferrite-garnet films with easy plane-type anisotropy
are discussed. The possibility of nonlinear magnetization oscillations occurring at a magnetizing pulse front several times
greater than the oscillation period is shown. The results from the calculations describe the actual shape of the longitudinal
and transverse signals quite well. The calculated values of the oscillation frequency (∼500 MHz) are also in good agreement
with the experimental data. 相似文献
7.
8.
Yu. Yu. Danilov S. V. Kuzikov V. G. Pavel’ev Yu. I. Koshurinov D. Yu. Shchegol’kov 《Technical Physics》2005,50(4):523-525
A pulse compressor using a three-mirror cavity is tested at a frequency of 34.27 GHz and a low power level. The cavity is
fed by a wave beam reflected from the corrugated mirror. The fourfold compression of a rectangular chirp is reached with an
efficiency of ≈60%. 相似文献
9.
R. A. Filatov Yu. A. Kalinin A. E. Khramov D. I. Trubetskov 《Radiophysics and Quantum Electronics》2006,49(10):769-778
We numerically simulate the influence of positive ions on characteristics of the microwave oscillations in a nonrelativistic
electron beam with the virtual cathode formed in a decelerating field (low-voltage vircator). A numerical scheme allowing
for ionization of a residual gas by an electron flow is proposed. It is shown that the residual-gas ionization in the operating
chamber of a low-voltage vircator leads to a forcing of the virtual cathode out of the transit gap and to a cutoff of microwave
oscillations. The obtained numerical data are confirmed by an experimental study using a low-voltage vircator model.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 49, No. 10, pp. 853–863, October 2006. 相似文献
10.
11.
Chang-Sing Hwang Mien-Win Wu 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1993,21(2):239-242
A radially extracted vircator (virtual-cathode oscillator) with two identical opposite output ports is presented. The microwave modes propagating inside the WR650 output rectangular waveguide are determined by the calibrated E -probes lined up in the direction perpendicular to the axis of the WR650 waveguide. Velvet-covered cathodes are used to emit electrons. Several diameters of velvet are chosen to see how the emitting area effects microwave generation. Evidence of virtual cathode formation, onset of electron reflexing, and simultaneous microwave emission are discussed. This vircator is found to have the capability of generating a maximum 1.4 GW microwave pulse with the dominant frequency at 8.2 GHz. The radiation pattern is dominated by the TE10 mode and the instantaneous efficiency for producing this microwave pulse is around 6±0.8%. Simple E-probes are applied to pick up the microwave signals inside the WR650 output rectangular waveguide 相似文献
12.
V. G. Kurin V. G. Skrynnik V. P. Shestopalov 《Radiophysics and Quantum Electronics》1993,36(11):779-784
The results of an experimental study of oscillation interaction in the open resonator of a diffraction radiation generator (DRG) are presented. Interaction is obtained in the region of oscillation splitting in the electrodynamic system of the DRG in the diffraction-radiation mode. The possibility of improving the generator's frequency stability in the vicinities of Morse critical points is shown.Institute of Radio Physics and Electronics, Academy of Sciences of Ukraine. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 36, No. 11, pp. 1023–1031, November, 1993. 相似文献
13.
V. N. Kornienko V. A. Cherepenin 《Bulletin of the Russian Academy of Sciences: Physics》2018,82(1):45-47
The dynamics of electron bunch formation are analyzed using data obtained by means of numerical simulation. It is shown that upon the development of microwave generation, electron bunches start to form in a relativistic flow in the first section of the electrodynamic structure. At the entrance to the second section, a complex structure of electron distribution over a longitudinal pulse is observed inside the bunch in the stationary mode of generation. It is concluded that the duration of a microwave radiation pulse can be increased by optimizing the length of the first section of the generator. 相似文献
14.
We study oscillation in a gyrotron with allowance for reflections from an output horn. Regions with different system behaviors,
such as stationary oscillation, self-modulation, and complex-dynamics regimes are found in the parameter plane. The scenarios
of appearance of chaotic oscillations are considered. It is shown that they can emerge via either a sequence of period-doubling
bifurcations or destruction of quasiperiodic motion. For chaotic attractors, Lyapunov exponents are calculated and their dimensions
are estimated on the basis of the Kaplan-Yorke formula. The dimension values turn out to be anomalously large, which is stipulated
by the presence of a large number of high-Q eigenmodes in the gyrotron cavity due to operation near the cutoff frequency of
an electrodynamic system.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 49, No. 10, pp. 887–899, October 2006. 相似文献
15.
对反馈调制型同轴虚阴极振荡器进行了理论分析和数值模拟研究,结果表明:该器件通过增加同轴谐振腔结构并引入反馈可以对入射电子束形成明显的调制效果,从而使得器件具有高束波转化效率和频率单一稳定的特性;同时输出微波的频率被器件结构中的同轴谐振腔锁定,调节腔参数可以在一定范围内对输出微波频率进行调谐;在二极管电压约为600 kV,电子束功率26.2 GW条件下,可以得到平均功率3.6 GW的微波输出,转换效率达到13.7%,主频为5.5 GHz,模式为TM02模。 相似文献
16.
We present simulations for a design of a high-energy single-stage mid-IR difference frequency generation adapted to a two-color Ti:sapphire amplifier system. The optimized mixing process is based on chirped pulse difference frequency generation (CP-DFG), allowing for a higher conversion efficiency and reduced two-photon absorption losses. The numerical start-to-end simulations include stretching, chirped pulse difference frequency generation and pulse compression. Realistic design parameters for commercially available nonlinear crystals (GaSe, AgGaS2, LiInSe2, LiGaSe2) are considered. Compared with conventional unchirped DFG directly pumped by Ti:sapphire technology, we predict a threefold increase in the quantum efficiency. Our CP-DFG scheme provides up to 340 μJ pulse energy directly at 7.2 μm when pumped with 8 mJ and supports a bandwidth of up to 350 nm. The resulting 240 fs mid-IR pulses are inherently phase stable. 相似文献
17.
Generation of terahertz radiation during reflection of femtosecond laser pulses from a metal surface
V. A. Mironov I. V. Oladyshkin E. V. Suvorov D. A. Fadeev 《Journal of Experimental and Theoretical Physics》2014,119(2):179-195
The features of terahertz radiation generated upon oblique incidence of a femtosecond laser pulse on a metal surface are investigated theoretically. We propose a Cherenkov-type generation mechanism associated with excitation of low-frequency surface currents by a p-polarized optical field. The nonlinear surface currents and corresponding electrodynamic characteristics of low-frequency radiation are calculated analytically and by numerical simulation using the hydrodynamic model. The features of Cherenkov generation of terahertz radiation are analyzed, and techniques are proposed for increasing efficiency. 相似文献
18.
结合低磁场返波管振荡器和虚阴极振荡器的优点,设计了一个具有较高效率的虚阴极振荡器,通过添加半反射腔,使虚阴极在由阳极箔、波导和半反射腔组成的准谐振腔内形成,实现器件的高效率、高功率运行。当电子能量和束流分别为480keV和23kA时,采用2.5维粒子模拟(PIC)程序模拟得到频率为3.7GHz、功率为2.6GW的微波输出,器件束波转换效率约为23%。 相似文献
19.