Characteristics of polymer velvet as field emitters under high-current pulsed discharge

Li, Limin; Liu, Lie; Chang, Lei; Wan, Hong; Wen, Jihong; Liu, Yonggui

doi:10.1016/j.apsusc.2008.11.076

Cited by 12 publications

(5 citation statements)

References 18 publications

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“…When the target surface is irradiated by electron beams with a small number, these carbides will facilitate the formation of individual microcraters having a high distribution density. However, the cathode plasma expands toward the anode at a speed of several cm/ms, rather than remaining on the cathode surface (Li et al, 2009a). Additionally, in the subsequent pulses, the ejection reoccurs at sites having residual carbides, and new craters form.…”

Section: Structure Of the Anode Surfacementioning

confidence: 99%

Layer structure, plasma jet, and thermal dynamics of Cu target irradiated by relativistic pulsed electron beam

Liu

Cheng

et al. 2009

Laser Part. Beams

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This paper, based on a relativistic electron-beam accelerator with inductive energy accumulation, investigates the layer structure, plasma jet, and thermal dynamics of Cu target under the irradiation of pulsed electron beam (350 kV, 4 kA, 300 ns). A description of a relativistic electron beam source with a carbon fiber cathode is presented. After the electron-beam irradiation at 13 J/cm 2 energy density, microcraters with 0.5-1 mm diameter appeared on the target surface, and the target cross section is characterized by multilayer structures with a 20 mm thickness melting layer and a cellular layer. Further, it was found that the carbon content increased significantly not only on the target surface but also on the cross section. The gas liberation per pulse induced by electron beam is analyzed. A good agreement between the experimental and calculated perveances was observed, with the exception at the end of the accelerating pulse possibly due to the participation of ion flow from the anode target. In the pulsed emission, there existed material transfer from anode to cathode, which is observed by the identification of elemental compositions on cathode surface. As the beam energy is deposited on target surface, the anode plasma jet is generated, and expands toward the cathode at a velocity of 3 cm/ms. By solving the one-dimensional heat equation, 10 9 K/s heating rate and 10 7 K/m temperature gradient can be obtained. After the heating of pulsed electron beam, the thermal conduction is dominant, with a cooling rate on the order of 10 7 K/s. The relativistic electron beam sources may provide a potential development for target experiments and high energy density physics.

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Section: Structure Of the Anode Surfacementioning

confidence: 99%

Layer structure, plasma jet, and thermal dynamics of Cu target irradiated by relativistic pulsed electron beam

Liu

Cheng

et al. 2009

Laser Part. Beams

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“…This rapidly excites a high voltage across the diode load, thus enabling the generation of high-current pulsed electron beam from explosive emission cathodes (Li et al, 2007(Li et al, , 2009a(Li et al, , 2009d. The turn-off time of EEOS depends on the wire length, wire material, and ambient mediums (different gases) (Sedoi et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Electrical explosion process and amorphous structure of carbon fibers under high-density current pulse igniting intense electron-beam accelerator

Liu

Cheng

et al. 2009

Laser Part. Beams

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The development of pulsed power technology, particularly for inductive energy storage, promotes the extensive discussions of electrical explosion process in high energy density. This paper presents the electrical-explosion behavior of carbon fibers subjected to about 20 kA, 5 ms high-density current pulse igniting an intense electron beam accelerator. After electrical explosion, and surface rupture, submicron particles, fibrillar and strip-shaped structures were observed, experimentally supporting the microstructure model (skin-core heterogeneity) of carbon fiber. Interestingly, the start and turn-off of the current were followed by radiation pulses with different intensities. It was found that the radiation was focused on the explosion stage which was characterized by an oscillating current. The instabilities of plasma produced during the explosion process play an important role in the microstructure changes of carbon fibers and the radiation generation.

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“…Velvet cloth, as a typical explosive emission cathode material, is still being investigated in high-power microwave tubes, but it does not have high electric and thermal conductivity [4,10,11]. Some semiconductor materials are also prepared as explosive emission cathodes, e.g.…”

Section: Introductionmentioning

confidence: 99%

“…These advantages of CsI-coated carbon fibre cathode come from the decrease in the work function of cathode materials by the CsI coating [16,17]. During the process of explosive electron emission, the emitters on the cathode surface bear a high temperature of hundreds of degrees and ion corrosion [1,11]. Under acidic conditions, ZnO or CuO has lower chemical stability than TiO 2 , potentially affecting the explosive emission cathode lifetime and bringing inconvenience to installation and storage.…”

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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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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Characteristics of polymer velvet as field emitters under high-current pulsed discharge

Cited by 12 publications

References 18 publications

Layer structure, plasma jet, and thermal dynamics of Cu target irradiated by relativistic pulsed electron beam

Layer structure, plasma jet, and thermal dynamics of Cu target irradiated by relativistic pulsed electron beam

Electrical explosion process and amorphous structure of carbon fibers under high-density current pulse igniting intense electron-beam accelerator

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

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Characteristics of polymer velvet as field emitters under high-current pulsed discharge

Cited by 12 publications

References 18 publications

Layer structure, plasma jet, and thermal dynamics of Cu target irradiated by relativistic pulsed electron beam

Layer structure, plasma jet, and thermal dynamics of Cu target irradiated by relativistic pulsed electron beam

Electrical explosion process and amorphous structure of carbon fibers under high-density current pulse igniting intense electron-beam accelerator

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

Contact Info

Product

Resources

About

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