Modelling of the Plasma–Sheath Boundary Region in Wall-Stabilized Arc Plasmas: Unipolar Discharge Properties

Mancinelli, B.; Prevosto, Leandro; Chamorro, Juan Camilo; Minotti, F.; Kelly, H.

doi:10.1007/s11090-017-9859-x

Cited by 7 publications

(11 citation statements)

References 76 publications

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“…A numerical investigation of the initial stage of the double-arcing phenomena with the focus on the kinetic processes is presented. This work is based on a previously reported fluid model, 4 which was used there to describe the properties of the unipolar-like, diffuse discharge in the plasma-sheath boundary region of a cutting arc torch operated with oxygen ( Fig. 1).…”

mentioning

confidence: 99%

“…More details on the equations of the model and the treatment of the transport and source terms can be found in Ref. 4.…”

mentioning

confidence: 99%

“…The boundary conditions for the model equations correspond in general to the conditions in Ref. 4. At the sheathplasma interface, axial profiles of plasma and gas densities as well as the electron temperature were specified as constant in time, thus imposing restrictions on the discharge time.…”

mentioning

confidence: 99%

“…The model equations were solved using the same numerical scheme as reported in Ref. 4. A uniform rectangular grid with 20 Â 20 mesh cells covered the rectangular model geometry.…”

mentioning

confidence: 99%

“…The double-arcing development was initiated by perturbing the diffuse discharge in the plasma-sheath boundary, 4 by a local rise in the surface electric field over a small area of the nozzle exit. Actually, such increase in the electric field can be associated with a change in the surface microstructure, 17 or the deposition of non-conducting films 7 on the nozzle wall.…”

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confidence: 99%

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Investigation of the relevant kinetic processes in the initial stage of a double-arcing instability in oxygen plasmas

et al. 2018

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A numerical investigation of the kinetic processes in the initial (nanosecond range) stage of the double-arcing instability was developed. The plasma-sheath boundary region of an oxygen-operated cutting torch was considered. The energy balance and chemistry processes in the discharge were described. It is shown that the double-arcing instability is a sudden transition from a diffuse (glow-like) discharge to a constricted (arc-like) discharge in the plasma-sheath boundary region arising from a field-emission instability. A critical electric field value of ∼107 V/m was found at the cathodic part of the nozzle wall under the conditions considered. The field-emission instability drives in turn a fast electronic-to-translational energy relaxation mechanism, giving rise to a very fast gas heating rate of at least ∼109 K/s, mainly due to reactions of preliminary dissociation of oxygen molecules via the highly excited electronic state O2(B3Σu−) populated by electron impact. It is expected that this fast oxygen heating rate further stimulates the discharge contraction through the thermal instability mechanism.

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confidence: 99%

“…More details on the equations of the model and the treatment of the transport and source terms can be found in Ref. 4.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

“…The model equations were solved using the same numerical scheme as reported in Ref. 4. A uniform rectangular grid with 20 Â 20 mesh cells covered the rectangular model geometry.…”

mentioning

confidence: 99%

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confidence: 99%

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Investigation of the relevant kinetic processes in the initial stage of a double-arcing instability in oxygen plasmas

et al. 2018

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Dry reforming of methane in an atmospheric pressure glow discharge: Confining the plasma to expand the performance

Wanten

Maerivoet

Vantomme

et al. 2022

Journal of CO2 Utilization

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Measurements of plasma density profile evolutions with a channel-guided laser

Yang¹,

Guo²,

Yan³

et al. 2023

High Pow Laser Sci Eng

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The discharged capillary plasma channel has been extensively studied as a high-gradient particle acceleration and transmission medium. A novel measurement method of plasma channel density profiles has been employed, where the role of plasma channels guiding the advantages of lasers has shown strong appeal. Here, we have studied the highorder transverse plasma density profile distribution using a channel-guided laser, and made detailed measurements of its evolution under various parameters. The paraxial wave equation in a plasma channel with high-order density profile components is analyzed, and the approximate propagation process based on the Gaussian profile laser is obtained on this basis, which agrees well with the simulation under phase conditions. In the experiments, by measuring the integrated transverse laser intensities at the outlet of the channels, the radial quartic density profiles of the plasma channels have been obtained. By precisely synchronizing the detection laser pulses and the plasma channels at various moments, the reconstructed density profile shows an evolution from the radial quartic profile to the quasi-parabolic profile, and the high-order component is indicated as an exponential decline tendency over time. Factors affecting the evolution rate were investigated by varying the incentive source and capillary parameters. It can be found that the discharge voltages and currents are positive factors quickening the evolution, while the electron-ion heating, capillary radii and pressures are negative ones. One plausible explanation is that quartic profile contributions may be linked to plasma heating. This work helps one to understand the mechanisms of the formation, the evolutions of the guiding channel electron-density profiles and their dependences on the external controllable parameters. It provides support and reflection for physical research on discharged capillary plasma and optimizing plasma channels in various applications.

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Modelling of the Plasma–Sheath Boundary Region in Wall-Stabilized Arc Plasmas: Unipolar Discharge Properties

Cited by 7 publications

References 76 publications

Investigation of the relevant kinetic processes in the initial stage of a double-arcing instability in oxygen plasmas

Investigation of the relevant kinetic processes in the initial stage of a double-arcing instability in oxygen plasmas

Dry reforming of methane in an atmospheric pressure glow discharge: Confining the plasma to expand the performance

Measurements of plasma density profile evolutions with a channel-guided laser

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