Dynamics of a high-density plasma in a magnetic field

Tsventoukh, M. M.; Shmelev, D. L.; Barengolts, S. A.

doi:10.1088/1361-6587/ab0790

Cited by 6 publications

(2 citation statements)

References 30 publications

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“…freezing state [26,27], due to the relatively low plasma density and collision frequency in the cathode spot jet mixing region. (5) Neglecting Lorentz forces in comparison to pressure gradients [28,29] in this paper.…”

Section: The Numerical Modelmentioning

confidence: 99%

Effect of ion collision on separation between light and heavy ions in multi-component vacuum arc

Sun,

Zhou,

Yang

et al. 2023

Plasma Sources Sci. Technol.

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In multi-component vacuum arc discharge, light ions and heavy ions usually have different spatial distributions of density and velocity. Previous research has suggested that the difference in spatial distribution of light and heavy ions is due to the mixing effect of cathode spot jet. However, in this work, the ion collision is found to be an important factor leading to the separation of light and heavy ions. In this paper, multi-fluid model is used to study the effect of ion collisions on separation mechanism in multi-component vacuum arc. The simulation results show that, during the jet mixing process, the collisions between different ions will reduce the velocity of light ions, and greatly increase the density and temperature. As a result, the pressure expansion of light ions is significantly enhanced. In addition, the collision between different ions will also increase the size of jet mixing region for light ions, which makes the plasma jet of light ions mixing more fully. These effects make their isotropic expansion dominant, and the ion density at the center is not much different from that at the edge. However for heavy ions, the collision between different ions has little influence on their movement. The pressure is far less than the inertia force, so the density of heavy ion mainly distributes along the convection direction, and the center is greater than the edge. This is the main separation mechanism of ion angular flux. It is also found there are three main factors leading to the separation of light and heavy ions: ion mass, ion density and ion temperature. The separation effect can be enhanced by increasing ion temperature, decreasing ion density and selecting electrode components with significant differences in elemental mass. This paper provides an insight into the mechanism of ion separation in multi-component vacuum arc.

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Section: The Numerical Modelmentioning

confidence: 99%

Effect of ion collision on separation between light and heavy ions in multi-component vacuum arc

Sun,

Zhou,

Yang

et al. 2023

Plasma Sources Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…The plasma is assumed to be quasi-neutral. (b) According to the theoretical estimation based on [25,26],…”

Section: The Basic Assumptionsmentioning

confidence: 99%

Study of ion separation mechanism in the multi-component vacuum arc discharge

Sun¹,

Zhou²,

Zhang³

et al. 2022

Plasma Sources Sci. Technol.

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The separation phenomenon of light and heavy ions was widely observed experimentally in the vacuum arc discharge with multi-component composite cathode. In this work, a two-dimensional axisymmetric multi-fluid model is used to study the separation mechanism in the multi-component composite cathode vacuum arc. The multi-component vacuum arcs are simulated as a whole which includes separate cathode spot jets, the mixing region, and common arc column. The results show that the plasma jets originated from the separate cathode spot mix together to form a common arc column after a certain distance from the cathode. Due to the rapid increase of ion temperature dozens of times in mixing region of cathode spot jet, the effect of pressure gradient becomes far greater than that of the collisions between light and heavy ions. This leads to a shift in the predominant ion motion mechanism from ion-ion collision (single cathode spot jet region) to pressure expansion (the mixing region). Finally, the light ions gain higher velocities under pressure expansion. In addition, the effect of thermal conductivity and viscosity leads to the wider high temperature regions for light ions, thus making a wider distribution of corresponding ion flux. The numerical results are qualitatively consistent with the experimental results. This paper provides an insight into ion separation mechanism in the multi-component vacuum arc.

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Numerical simulation of cathode-spot crater and droplet formation with linear and circular motion process

Wang,

Gao

et al. 2024

J. Phys. D: Appl. Phys.

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In this paper, a three-dimensional cathode spot erosion model is proposed to study the development of cathode spot motion process on the surface of copper cathode. The formation and development process of cathode spots motion without external magnetic field is studied. In this model, energy flux density, pressure, and current value are considered as external parameters. The simulation results compared the cathode spot ablation trajectories and temperature distribution under different motion forms and motion velocities. The results indicated that during the spots expansion process, the flow of liquid metal will form a convex structure on the surface of the cathode and a hollow structure inside the cathode. Comparing different motion types, the annular motion significantly increased the roughness of the cathode surface. With the increase of the speed of spots movement, the interaction between the craters is significantly weakened, which will reduce the temperature and the roughness of the cathode surface. The simulation results are consistent with the experimental results.

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Dynamics of a high-density plasma in a magnetic field

Cited by 6 publications

References 30 publications

Effect of ion collision on separation between light and heavy ions in multi-component vacuum arc

Effect of ion collision on separation between light and heavy ions in multi-component vacuum arc

Study of ion separation mechanism in the multi-component vacuum arc discharge

Numerical simulation of cathode-spot crater and droplet formation with linear and circular motion process

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