Activation of the explosive-emission cathode under various conditions of preinitiation

Shunaĭlov, S. A.; Yalandin, M. I.; Sharypov, K. A.; Kolomiets, M. D.; Ul’masculov, M. R.; Shpak, V. G.; Rostov, V. V.; Mesyats, G.

doi:10.1016/j.vacuum.2017.03.012

Cited by 7 publications

(2 citation statements)

References 29 publications

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“…For vacuum electron tubes and accelerators requiring highcurrent and high-voltage electron beams, field emission materials are typically used as high-current electron beam emitters (with current density on the order of kA cm −2 ) [1][2][3]. Under the application of high voltage pulses (>10 kV), some cathode plasma spots as the initial form of cathode plasma are generated on inhomogeneous sites such as impurities, microprotrusions or sharp edges, where the microscopic electric field is enhanced significantly [4,5].…”

Section: Introductionmentioning

confidence: 99%

“…Recently, a hybrid disordered carbon fibre cathode with ideal electric resistance was reported by Lu et al [12]. To date, carbon fibres are considered one of the most appropriate candidates for explosive emission cathodes to generate electron beams with high current densities due to its outstanding vacuum compatibility, fast turn-on, low plasma expansion velocity and operational stability [1][2][3]13]. The bottleneck of developing carbon fibre cathodes for explosive electron emission is generating largearea cathode plasma with a rapid turn-on time.…”

Section: Introductionmentioning

confidence: 99%

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Cold atmospheric pressure plasma jet prepares TiO₂ coating on carbon fibre for field emission and explosive electron emission

Zhiwei¹,

Ma²,

Liu³

et al. 2021

J. Phys. D: Appl. Phys.

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As the 'heart' of high-current vacuum electronic devices, explosive emission cathodes play an important role in their applications. In this work, a titanium dioxide (TiO 2 )/carbon fibre cathode prepared by a cold atmospheric plasma jet is reported. TiO 2 on the carbon fibre surface prepared by an atmospheric plasma jet is at the mixture of anatase and rutile phases. The field enhancement factor of the TiO 2 /carbon fibre cathode is 6681, which is over ten times higher than that of the carbon fibre cathode. Furthermore, the TiO 2 coating slows the diode impedance collapse and decreases the cathode plasma expansion velocity from 1.5-2.0 to 1.0-1.5 cm µs −1 , which is explained by a cathode plasma model. The surface of the TiO 2 /carbon fibre cathode is covered by 1.6 cm 2 plasma, far exceeding that of the carbon fibre cathode (1.1 cm 2 ), which enables uniform explosive electron emission. The obtained results show that TiO 2 /carbon fibre cathodes prepared by cold atmospheric plasma jets will be potential candidates as high-current explosive electron emitters.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cold atmospheric pressure plasma jet prepares TiO₂ coating on carbon fibre for field emission and explosive electron emission

Zhiwei¹,

Ma²,

Liu³

et al. 2021

J. Phys. D: Appl. Phys.

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Effect of a submicrosecond-advanced voltage pulse on the formation of a high-current electron beam in a magnetically insulated coaxial diode

et al. 2018

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The effect of a double accelerating voltage pulse on the formation of a high-current electron beam in a magnetically insulated coaxial diode under fore-vacuum pressures has been investigated. High voltage pulses of durations <0.5 and ∼1 ns and amplitudes (modulo) <120 and ≥ 160 kV, respectively, were applied to a graphite cathode with a submicrosecond delay. When the time delay between the pulses was increased to a certain value at a residual gas pressure of 5 × 10−3 Torr, the current of the second beam increased about fourfold and then decreased. The current reached a maximum of 4.5 kA, which was greater than that carried by the matched load of the high voltage generator. The observed effect can be accounted for by the neutralization of the beam charge in the plasma expanding from the cathode. The plasma channel could be formed due to explosive electron emission from the cathode or due to impact ionization of the residual gas.

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A phase-stabilized superradiant Ka-band oscillator driven by nanosecond voltage pulses with amplitude variations and reduced rise rates

Sharypov

Rostov

Sadykova

et al. 2018

Applied Physics Letters

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This paper presents the results of experiments and a numerical simulation of the conditions for phase stabilization (standard deviation < 0.5 rad) of a subgigawatt relativistic superradiant Ka-band backward wave oscillator with the accelerating voltage amplitude varying within 15%. It is shown that phase stabilization can be achieved for the voltage rise rate (dU/dt)max ∼ 2 MV/ns by using our recently developed approach. Particular emphasis is given to the cases of substantially lower voltage rise rates at which stabilization of the microwave oscillation phase is also possible. The mode with (dU/dt)max ≪ 1 MV/ns is considered for specific voltage waveforms that ensure efficient kinematic peaking of the beam current. In this case, stabilization of the microwave oscillation phase can be achieved by initiating a voltage prepulse, provided that the accelerating pulse leading edge has a segment of stable rise rate and stable shape.

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Activation of the explosive-emission cathode under various conditions of preinitiation

Cited by 7 publications

References 29 publications

Cold atmospheric pressure plasma jet prepares TiO₂ coating on carbon fibre for field emission and explosive electron emission

Cold atmospheric pressure plasma jet prepares TiO₂ coating on carbon fibre for field emission and explosive electron emission

Effect of a submicrosecond-advanced voltage pulse on the formation of a high-current electron beam in a magnetically insulated coaxial diode

A phase-stabilized superradiant Ka-band oscillator driven by nanosecond voltage pulses with amplitude variations and reduced rise rates

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Activation of the explosive-emission cathode under various conditions of preinitiation

Cited by 7 publications

References 29 publications

Cold atmospheric pressure plasma jet prepares TiO2 coating on carbon fibre for field emission and explosive electron emission

Cold atmospheric pressure plasma jet prepares TiO2 coating on carbon fibre for field emission and explosive electron emission

Effect of a submicrosecond-advanced voltage pulse on the formation of a high-current electron beam in a magnetically insulated coaxial diode

A phase-stabilized superradiant Ka-band oscillator driven by nanosecond voltage pulses with amplitude variations and reduced rise rates

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Product

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Cold atmospheric pressure plasma jet prepares TiO₂ coating on carbon fibre for field emission and explosive electron emission

Cold atmospheric pressure plasma jet prepares TiO₂ coating on carbon fibre for field emission and explosive electron emission