共查询到20条相似文献,搜索用时 31 毫秒
1.
M. A. Moiseev L. L. Nemirovskaya V. E. Zapevalov N. A. Zavolsky 《International Journal of Infrared and Millimeter Waves》1997,18(11):2117-2128
The paper presents an advanced method for and results of calculating main parameters of CW 170 GHz/1 MW gyrotrons operating
at the TE28.7 and TE31.8 modes for ITER. Parameters are optimized to achieve maximum efficiency of the gyrotron with an acceptable Ohmic load on the
cavity. Numerical modeling of starting up a gyrotron with an optimized cavity and processes of mode interaction are discussed. 相似文献
2.
T. Idehara T. Saito H. Mori H. Tsuchiya La Agusu S. Mitsudo 《International Journal of Infrared and Millimeter Waves》2008,29(2):131-141
Long pulse operation up to 1 msec of a high frequency gyrotron with a pulse magnet has been successfully carried out in a
frequency range including 1 THz. In the experiments, the timing of an electron beam pulse injection is adjusted at the top
of the magnetic field pulse, where the variation of field intensity is negligible. The operation cavity modes seem to be TE1, 12 and TE4,12 at the second harmonics. The corresponding frequencies are 903 GHz and 1,013 GHz, respectively. Additionally several features
of radiation measurement results of the gyrotron are described and brief considerations are presented. 相似文献
3.
Zavol'sky N. A. Zapevalov V. E. Moiseev M. A. Nemirovskaya L. L. 《Radiophysics and Quantum Electronics》2004,47(8):603-614
We calculated the optimal parameters of a low-Q cavity of a millimeter-wavelength continuous-wave gyrotron which ensure that the maximum efficiency is reached for a limited heat load on the cavity wall. The influence of the cavity optimization on the efficiency of energy recovery of a collector electron beam is considered. Stability of the operating mode to self-excitation of other modes is studied. Gyrotrons with radiation power 1 MW, frequency range 140–170 GHz, and operating modes TE22.6 and TE25.10 are studied as the example. The obtained results are generalized to gyrotrons with other operating modes and frequencies. 相似文献
4.
THE FIRST EXPERIMENT OF A THz GYROTRON WITH A PULSE MAGNET 总被引:1,自引:0,他引:1
T. Idehara H. Tsuchiya O. Watanabe La Agusu S. Mitsudo 《International Journal of Infrared and Millimeter Waves》2006,27(3):319-331
A THz gyrotron with a pulse magnet has been designed, constructed and operated in FIR FU. It is developed as one of high frequency
gyrotrons included in Gyrotron FU Series. The gyrotron has already achieved the first experimental result for high frequency
operations whose radiation frequency exceeds 1 THz. In this paper, the design detail and the operation test results for sub-terahertz
to terahertz range are described. The second harmonic operation is confirmed experimentally at the expected frequency of 1.005
THz due to TE6,11 cavity mode at the magnetic field intensity of 19.0 T. 相似文献
5.
La Agusu T. Idehara I. Ogawa T. Saito T. Kanemaki H. Takahashi T. Fujiwara 《International Journal of Infrared and Millimeter Waves》2007,28(7):499-511
A CW gyrotron for the sensitivity enhancement of NMR spectroscopy through dynamic nuclear polarization has been designed.
The gyrotron operates at the second harmonic and frequency of 394.6 GHz with the main operating mode TE0,6. Operating conditions of other neighboring cavity modes such as TE2,6 at frequency of 392.6 GHz and TE2,3 at frequency of 200.7 GHz were also considered. The experimental conditions of the gyrotron at low and high voltages are
simulated. The output power of 56 watts corresponds to the efficiency of 2 percent at low voltage operation and frequency
of 394.6 GHz is expected. 相似文献
6.
O. Dumbrajs 《International Journal of Infrared and Millimeter Waves》1990,11(1):61-67
A self—consistent calculation of the self—modulation instability in gyrotrons operating in whispering gallery modes is carried out in the cold cavity approximation for satellite modes. The approach is illustrated numerically in the case of the planned operation of the KfK gyrotron in the TE10,4 mode. 相似文献
7.
T. Idehara I. Ogawa La Agusu T. Kanemaki S. Mitsudo T. Saito T. Fujiwara H. Takahashi 《International Journal of Infrared and Millimeter Waves》2007,28(6):433-442
Gyrotron FU CW II with an 8 T liquid He free superconducting magnet, the second gyrotron of the THz Gyrotron FU CW Series,
has been constructed and the operation test was successfully carried out. It will be used for enhancing the sensitivity of
600 MHz proton-NMR by use of Dynamic Nuclear Polarization (DNP). The designed operation mode of the gyrotron is TE2,6 at the second harmonic. The corresponding frequency is 394.6 GHz. The real operation frequency is 394.3 GHz at TE06 mode, because of fabrication error of the diameter of the cavity. The operation is in complete CW at the output power of
around 30 W or higher at the TE06 cavity mode. There are many other operation modes at the fundamental and the second harmonic. Typical output power of the
fundamental and the second harmonic are higher than 100 W and 20 W, respectively. The highest frequency observed up to the
present is 443.5 GHz at the second harmonic operation of TE6,5 mode. The measured results are compared with the theoretical consideration. 相似文献
8.
9.
I. Ogawa K. Yamada T. Idehara R. Pavlichenko 《International Journal of Infrared and Millimeter Waves》2002,23(2):189-203
In this paper we present a novel design of a quasi-optical system for conversion of gyrotron outputs into Gaussian-like beams. It consists of a quasi-optical antenna, two focusing mirrors and a filter which removes the side lobes of the beam. The system is appropriate as a transmission line for frequency tunable gyrotrons operating at TE0n mode. As an illustration of our approach, we present results which demonstrate the applicability of the developed system for conversion of the radiation generated by the Gyrotron FU IVA. The examples include conversion of three TE0n modes (TE02, 223 GHz; TE03, 323 GHz; TE04, 423 GHz) into Gaussian- like beams. 相似文献
10.
Shi-Chang Zhang 《International Journal of Infrared and Millimeter Waves》2000,21(4):547-551
Comparative study is presented to the effect of the electron-beam misalignment on the starting current and output power of the coaxial-cavity and cylindrical-cavity gyrotron oscillators operating in the millimeter wave ranges. The numerical analysis is based on the gyrokinetic formulas for a TE28,16,1 mode at a frequency of 140 GHz. Results show that the coaxial-cavity gyrotron oscillator has lower starting current and less power loss than the cylindrical-cavity gyrotron oscillator when the electron-beam axis has a misalignment to the cavity axis. 相似文献
11.
O. Dumbrajs La Agusu T. Idehara 《International Journal of Infrared and Millimeter Waves》2006,27(9):1159-1171
Influence of magnetic field tapering on operation of a gyrotron working in the TE
4,12 mode at the second harmonic frequency 1013.67 GHz is investigated. It is found that the existing inhomogeneity of the magnetic
field of the order of 0.25%–0.50% in the cavity allows one to achieve higher efficiencies. It improves also mode competition
scenario by suppressing oscillations of the two parasitic TE
3,6+ and TE
5,5− modes at the fundamental frequencies 513.35 GHz and 503.64 GHz, respectively. 相似文献
12.
R. J. Temkin K. E. Kreischer W. J. Mulligan S. MacCabe H. R. Fetterman 《International Journal of Infrared and Millimeter Waves》1982,3(4):427-437
The design and operation of a 100 kW, 140 GHz pulsed gyrotron are reported. To our knowledge, this is the highest frequency at which high gyrotron output power (>-100 kW) has been achieved. Results are presented for gyrotron operation in the range of magnetic field from 4 to 7 T, voltage from 23 to 80 kV and current up to 7.5 A. Near a value of magnetic field of 5.4 T, and output power of 100 kW was obtained at 140.4 GHz in single mode operation in the TE031 resonator mode. 相似文献
13.
X. Yang A. Arnold E. Borie G. Dammertz O. Drumm K. Koppenburg B. Piosczyk D. Wagner M. Thumm 《International Journal of Infrared and Millimeter Waves》2004,25(11):1557-1566
A broadband quasi-optical (QO) mode converter for a multi-frequency gyrotron has been designed and tested at Forschungszentrum Karlsruhe (FZK). The launcher is optimized for the TE22,8 mode at 140 GHz, but the radiated beams present an almost identically focused pattern for all 9 considered modes between 105 GHz (TE17,6) and 143 GHz (TE23,8). Combining with a beam-forming mirror system, which consists of a quasi-elliptical mirror and two phase-correcting mirrors with non-quadratic surface contour, further calculations show that efficiencies of more than 94% have been achieved for converting the rotating high-order cylindrical cavity modes into the usable fundamental Gaussian mode. Low power (cold) measurements show a good agreement with theoretical predictions. This QO mode converter can be used for the broadband operation of a multi-frequency 1 MW gyrotron. 相似文献
14.
定义了光子带隙谐振腔(photonic-band-gap cavity, PBGC)的等效半径,论证了使用该半径将PBGC等效为具有模式选择性的金属圆柱谐振腔的有效性,揭示了其在PBGC设计过程中的指导性作用.基于等效半径的运用,建立起光子带隙谐振腔回旋管振荡器(PBG回旋管)的自洽非线性理论,并对工作于TE32模的PBG回旋管作了理论分析和数值计算.目前的研究表明:高频电磁场沿角向呈行波或驻波的不同极化形式对PBG回旋管的注-波互作用过程具有较大的影响;较之电子回旋基波,该器件中二
关键词:
光子带隙谐振腔
等效半径
回旋管
自洽非线性理论 相似文献
15.
P. J. Castro J. J. Barroso R. A. Correa M. C. A. Nono 《International Journal of Infrared and Millimeter Waves》1992,13(1):91-104
Experiments have been conducted to characterize a gyrotron cavity designed to operate in theTE
021 mode at 10 GHz. Cavity excitation was accomplished via a coupling hole introduced into the cavity wall and mode detection was carried out by means of two experimental arrangements. In the first, electromagnetic energy is coupled into a receiving waveguide through a small second hole drilled in the opposite side of the cavity. The other scheme uses a horn antenna to receive the power reradiated by the open resonator. Both schemes are discussed regarding mode detection, and measured data includes resonant frequency, loadedQ factor, axial electric field profile and farfield radiation pattern. Evaluation of the loadedQ factor is based on bandwidth measurements whereas standing-wave electric field profile is determined by using perturbation techniques. For severalTE modes, close agreeent between theory and experiment is found. 相似文献
16.
We design a single-ridged coaxial hybrid coupler which excites a TE011 mode of high mode content in a cylindrical cavity, resonating at 28.2GHz. The coupler consists of a WR-28 rectangular waveguide, a coaxial TEn11 cavity, and a cylindrical TE011 cavity. Both TE311 coaxial cavity and TE411 single-ridged coaxial cavity are analyzed to examine the TE011 mode purity in the central cavity. Mode purity analysis is performed by a field expansion method using Fourier-Bessel orthonormal basis functions. Numerical calculations predict that the TE411 single-ridged coaxial cavity excites the TE011 mode with mode purity of 98.6%, which is improved by 3% higher compared with the TE311 coaxial cavity. Measurements on the single-ridged coaxial coupler show a resonant frequency at 28.078GHz and ohmic and external Qs of 1560, 473 respectively, which are in good agreement with the simulated results of a 3-D finite element electromagnetic code. 相似文献
17.
The design and the numerical simulation of the interaction cavity for 120 GHz, 1 MW gyrotron is presented. The optimizations of the cavity parameters are carried out by using the Particle-in-Cell, 3D-electromagnetic simulation code MAGIC. The co-rotating TE22,6 mode is selected by using the in-house developed code GCOMS. The cold cavity and the beam–wave interaction analyses are carried out to analyze the eigenmode, eigenfrequency and the output power performance. The output power more than 1 MW is achieved at the magnetic field of 4.82 T. The sensitivity analyses of the output power and the frequency with respect to the various interaction cavity parameters are also performed. 相似文献
18.
V. V. P. Singh E. Borie A. K. Sinha B. N. Basu H. N. Bandopadhyay 《International Journal of Infrared and Millimeter Waves》2000,21(4):485-504
This paper investigates the possibility of using Silicon Nitride Composite (Kyocera SN-287) as single-disc, edge-cooled window for gyrotrons operating below 200 kW CW in the frequency range 28-42 GHz. Rotationally symmetric TE0n, and TEM00 Gaussian modes of rf transmission through the window have been considered. Analysis performed using a one dimensional (1D) finite difference (FD) code reveals that thermal stresses developed due to non-uniform temperature distribution on the disc surface are well within manageable limits for a 200 kW 42 GHz gyrotron proposed for some ECRH applications. For industrial gyrotrons, for microwave material processing and operating at a maximum power level of 100 kW CW, Si3N4 windows may be a cost effective replacement for sapphire windows. It is found that a TE02 profile results in lower peak temperature at the window disc in comparison to a Gaussian beam profile and allows the use of smaller discs. 相似文献
19.
Shi-Chang Zhang 《International Journal of Infrared and Millimeter Waves》2001,22(4):571-576
A gyrokinetic analysis is presented to the influence of the electron beam eccentricity on the power and starting current of a coaxial cavity gyrotron, which operates in a higher-order mode TE31, 17, 1 with a frequency of 165 GHz. It is found that the starting current becomes larger because of the existence of the electron-beam eccentricity. Especially, the power will be decreased substantially by the electron beam eccentricity, for example, down to 93% of the power without any eccentricity even if the eccentricity is 1% of the outer conductor radius. The acceptable range of the electron beam voltage and operating magnetic field for the establishment of the electromagnetic oscillation is narrowed by the electron-beam eccentricity. 相似文献
20.
O. Dumbrajs M. Thumm J. Pretterebner D. Wagner 《International Journal of Infrared and Millimeter Waves》1992,13(6):825-840
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 TE10,4 mode is used as an example. Cavity and adjacent tapered output waveguide are optimized as a single unit. 相似文献