A vacuum-sealed, gigawatt-class, repetitively pulsed high-power microwave source

Xun, Tao; Yang, Fan; Yang, Hanwu; Zhang, Zicheng; Chen, Dongqun; Zhang, Jiande

doi:10.1063/1.4986632

Cited by 5 publications

(3 citation statements)

References 21 publications

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“…Since HPM studies require a special category of compact, repetitive pulse generators (electron beam accelerators), pulsed power drivers especially devoted to HPM are also widely researched, and they also have a very wide range of parameters in peak power, pulse width, impedance, rep-rate, etc. For example, a promising HPM device, the magnetically insulated transmission line oscillator (MILO) [7][8][9][10][11], which is compact and requires no guiding magnetic field, requires a low impedance HPM driver of the following electrical parameters: power in the range of tens gigawatt, impedance around 10 Ω, pulse width around 100 ns, repetition rate of 1-10 Hz, etc. The accelerators should also be as compact, efficient, and reliable as the state-of-the-art technology can achieve at a reasonable cost.…”

Section: Introductionmentioning

confidence: 99%

A Repetitive Low Impedance High Power Microwave Driver

et al. 2022

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A low impedance high power microwave (HPM) driver is designed, which can be used in studying multi-gigawatt HPM devices such as the magnetically insulated transmission line oscillator (MILO), based on a helical pulse forming line (PFL) and the Tesla pulse transformer technology. The co-axial PFL is insulated by ethanol–water mixture, whose dielectric constant can be adjusted; and the helical line increases the output pulse width as well as the impedance to make a better match with the load. By the optimal combination of PFL charging voltage and output switch working voltage, the reliability of the PFL can be improved. The Tesla transformer has partial magnetic cores to increase the coupling coefficient and is connected like an autotransformer to increase the voltage step-up ratio. The primary capacitor of the transformer is charged by a high voltage constant current power supply and discharged by a triggered switch. A transmission line is installed between the PFL and the HPM load, to further increase the load voltage. A ceramic disk vacuum interface is used for improving the vacuum of the HPM tube. The experiments show that the driver can operate at 30 GW peak power, 75 ns pulse width and 5 Hz repetition rate.

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Section: Introductionmentioning

confidence: 99%

A Repetitive Low Impedance High Power Microwave Driver

et al. 2022

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“…In 2014, J M Parson et al (TTU) [12] conducted experiments on a high-power microwave (HPM) sealed-tube virtual cathode oscillator (vircator) at a voltage of 50 kV and a pulse width of 50 ns under a repetition rate of 200 Hz, where the background pressure was 1.3 × 10 −7 Pa and the equilibrium pressure was less than 1.3 × 10 −4 Pa. In 2017, T Xun et al [13] carried out 5 Hz repetition rate experiments on a magnetically insulated line oscillator (MILO) microwave source under a diode voltage of 630 kV and a beam current of 43 kA. The output pulse width was greater than 40 ns, and the equilibrium pressure was less than 5.0 × 10 −2 Pa.…”

Section: Introductionmentioning

confidence: 99%

A Dynamic Pumping Model for a Vacuum-Sealed Gigawatt Repetitively Operated High-Power Microwave Source

et al. 2022

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In this study, a dynamic pumping model was established for a vacuum-sealed, gigawatt-class, repetitively operated transit-time oscillator (TTO) based on the direct-simulation Monte Carlo (DSMC) method, and the pressure distribution of the model at different times and locations was analyzed. The simulation results showed that the maximum pressure at the diode was an order of magnitude larger than the equilibrium pressure, and the pressure recovery time was three times the duration of a single pulse. To verify the accuracy of the simulation results, experiments were conducted in a vacuum-sealed hard-tube TTO structure with a repetition rate of 10 Hz and the pressure was monitored at the vacuum diode. The diode voltage was about 500 kV and the beam current was 8 kA. Further, the average microwave power was 1 GW with a pulse width of 40 ns. The experimental results revealed that the equilibrium pressure at the vacuum diode was 4.0 × 10−3 Pa, and the pressure recovery time was three times the duration of a single pulse. These results were consistent with the simulation results, which indicates that the proposed model can provide technical support for subsequent vacuum-maintenance experiments.

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“…Due to the possible surface flashover under high-power flow, the vacuum interface has become the potential limiting factor [2], [3]. Besides, vacuum interface is crucial to ensure the vacuum condition of the high-current beam source, the microwave source, and the radiating antenna in the HPM system [4], [5]. The strict control of the gas source is based on the use of fully enclosed microwave tube technology, requiring a ceramic-metal packaging at the vacuum interface of the high-current beam source.…”

Section: Introductionmentioning

confidence: 99%

Developments of Pulsed Electron Beam Sources for High-Power Microwave Applications

et al. 2020

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High-current pulsed electron beam sources are the core components of high-power microwave systems. In order to meet the requirements of future applications, one needs to improve the performance of electron beam sources in terms of vacuum insulation, beam transportation, and thermal management. In this paper, we report about our recent progress in the development of high-current vacuum electron beam sources. In order to meet the vacuum maintenance requirements of high-power microwave tubes, a high-electric field ceramic vacuum interface is designed and fabricated based on the ceramic metal brazing technique. In our experiments, a stable operation of the ceramic vacuum interface is demonstrated in the 10 Hz repetition mode with withstand voltage of larger than 600 kV and pulse width of about100 ns. Besides, a cold cathode is developed using SiC nanowires, and an average beam current density of 1.2 kA/cm 2 is achieved under the electric field strength of 90 kV/cm. Compared with traditional velvet cathodes, the characteristics of the SiC nanowire cathode, such as macro-electrical stability, emission uniformity, and operating life have been significantly improved. Furthermore, a high-current electron beam collector has been developed for relativistic backward wave oscillator tubes. A spiral flume is designed in the collector to meet the requirement of both high specific energy and low flow rate. It shows that the withstand heat flow density is in the order of 10 12 W/m 2 , which is suitable for the long pulse and repetitive operation of the system. These results represent a significant step towards the practical application of long-life high-power microwave systems.INDEX TERMS High-current sources, vacuum interface, ceramic flashover, nano-cathode, collector, thermal control, high-power microwave devices.

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A vacuum-sealed, gigawatt-class, repetitively pulsed high-power microwave source

Cited by 5 publications

References 21 publications

A Repetitive Low Impedance High Power Microwave Driver

A Repetitive Low Impedance High Power Microwave Driver

A Dynamic Pumping Model for a Vacuum-Sealed Gigawatt Repetitively Operated High-Power Microwave Source

Developments of Pulsed Electron Beam Sources for High-Power Microwave Applications

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