A simplified fluid model of the metallic plasma and neutral gas interaction in a multicathode spot vacuum arc

et al. 2004

Section: ͑2͒mentioning

confidence: 99%

Differences in the metallic plasma-neutral gas structure in a vacuum arc operated with nitrogen and argon

Grondona

Márquez

et al. 2004

“…16 Although it was found in Ref. 15 that the electron temperature behavior was quite uncoupled from the ion dynamics, it is clear that any calculation ͑or estimation͒ of several inelastic processes between electrons and neutral gas particles requires a proper electron temperature profile. Finally, in Ref.…”

Section: Introductionmentioning

confidence: 99%

“…In all of these studies, the radius R was thought to represent an impermeable barrier ͑shock wave͒ separating two gas-like volumes, the metallic plasma and the neutral gas. More recently, Kelly et al 15 presented a steady fluid model with spherical symmetry to describe the elastic interaction between metallic plasma and neutral gas in the outer region of the arc channel, taking into account the local balances of momentum and energy, and the heating and ensuing expansion of the surrounding gas. The set of equations included a charge neutrality equation, ion continuity and momentum, electron momentum and energy, and neutral momentum and energy equations.…”

Section: Introductionmentioning

confidence: 99%

“…In the second place, it was assumed in Ref. 15 that, in the absence of a significant metallic-ion recombination, the electron drift velocity should be equal to zero. Although this assumption looks reasonable since it was experimentally found that metallic shields biased to the ground cathode potential always collected a pure ion current, [6][7][8][9] it would be desirable that the condition of zero electron drift velocity in the vicinities of the chamber wall can be obtained consistently from the model results.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Structure of plasmas generated by the interaction between metallic ions and neutral gas particles in a low-pressure arc

Kelly

Lepone

2000

Self Cite

A numerical solution for the metallic-plasma-neutral-gas structure generated in a low-pressure arc is presented. The equations correspond to a spherically symmetric fluid-like steady model, valid for the outer region of the arc, and describe the ion slowing down by elastic scattering with the neutral particles. Technically, the obtention of the profiles of different magnitudes is complicated due to the existence of a critical point in the steady-state system of equations. The proposed approach to overcome this difficulty is to solve instead a pseudotransient system of equations which rapidly and efficiently relax to the stationary state. By employing this numerical method of second-order accuracy in space, the plasma and neutral gas density, the electron and ion drift velocities, the electron and neutral temperatures, and the electrostatic potential profiles are obtained from the border of the arc channel up to the discharge chamber wall. It is found that the value of the neutral gas filling pressure strongly influences the plasma density and plasma potential distributions. An important result is that metallic ions emitted from the arc channel deliver their kinetic energy to the filling gas in a gradual manner, up to a pressure-dependent point beyond which they move to the walls sustained against collisions with the gas by a self-consistent electric field. Near the mentioned point, the metallic ion density presents a peculiar behavior, showing an increase that is more pronounced at high pressures; a pattern also evident in the electrostatic potential.

“…Some of them were mainly related to the study of elastic interactions between metallic ions and neutrals. [8][9][10][11][12] Other studies referred to inelastic interactions in the interelectrode region. From photon and ion emission studies, [13][14][15] it was concluded that charge-exchange reactions were the main channel for metallic ion losses, in a gas pressure ͑p͒ range of 10 −6 -10 −2 mbar.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamic model for a vacuum arc operated with background gas: Theory and experimental validation

Grondona

Kelly

2006

Self Cite

Differences in the metallic plasma-neutral gas structure in a vacuum arc operated with nitrogen and argon J. Appl. Phys. 96, 3077 (2004) A stationary, one-dimensional fluid model is presented to describe the interelectrode region of a nonfiltered vacuum arc operated with a background gas. The model includes the electron energy equation and the main elastic and inelastic atomic processes among metallic ions, electrons, and gas particles. To validate the model predictions an experimental study of the plasma-neutral gas structure, using a titanium ͑Ti͒ cathode and argon ͑Ar͒ as the background gas, is presented. The measured electron temperature and the experimental dependence on the pressure of neutral Ti and Ar spectroscopic emission lines are well reproduced, using a simple atomic model to interpret the plasma radiation emission.