Simulation of the prebreakdown processes in a cathode microprotrusion with the tip shape varying due to melting

Uimanov, I.V.; Shmelev, D.L.; Barengolts, S.A.

doi:10.1016/j.vacuum.2023.112823

Cited by 3 publications

(2 citation statements)

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“…The minimum cathode temperature of 6000 K is chosen to obtain stationary solutions [24]. The maximum cathode temperature of 8000 K is selected for the critical temperature of the copper for explosive emission [14,44,45]. The electron temperatures are referring to the previous cathode spot studies [16,17,20,26].…”

Section: Input Parametersmentioning

confidence: 99%

“…Experimental measurements have reported vacuum arc discharge voltages within the range of 10 volts [6][7][8][9]. The operating temperature of the cathode has been estimated at several thousand kelvins in various models [10][11][12][13][14]. Investigating how the vacuum arc plasma varies across these wide-ranging discharge parameters can significantly enhance our understanding of the vacuum arc discharge process.…”

Section: Introductionmentioning

confidence: 99%

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Numerical study on the effects of discharge parameters on vacuum arc plasma

Song,

Yang,

Sun

et al. 2024

J. Phys. D: Appl. Phys.

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Studying the characteristics of vacuum arc plasma within a wide range discharge parameters is vital for vacuum arc applications. In this study, specific parameters of vacuum discharge, including cathode temperature ranging from 6000 to 8000 K, emitted electron temperature spanning from 0.69 to 2.5 eV, and arc burning voltage within the range of 16-30 V, have been selected to analyze the effects of these parameters on the cathode erosion, cathode potential drop, and ion velocity. A validated one-dimensional spherical PIC-DSMC cathode spot model is employed to simulate the generation and expansion of vacuum arc plasma. The results indicate that increasing the cathode temperature and the emitted electron temperature both enhance the cathode eroded mass. However, this mass diminishes as the arc voltage increases due to more Cu ions and Cu atoms return to cathode under the high cathode potential drop and charge exchange collision, respectively. The cathode current density remains nearly constant within the explored range of cathode temperature, but increases as shifting the emitted electron temperature and arc voltage. A higher cathode current density, coupled with the positive cathode plasma resistance, induces a higher cathode potential drop that significantly surpasses the cathode sheath voltage. Furthermore, a higher ion velocity is observed at increased arc voltage due to the higher cathode current density generate stronger electron friction for accelerating ion. These findings could be valuable in designing a suitable arc voltage in vacuum electric thrusters to enhance thrust.

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Section: Input Parametersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical study on the effects of discharge parameters on vacuum arc plasma

Song,

Yang,

Sun

et al. 2024

J. Phys. D: Appl. Phys.

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The effect of viscosity on the self-similar growth of conic cusps on the surface of a conducting liquid in an electric field: Limiting cone angle

Zubarev

2024

Physics of Fluids

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The dynamics of the formation of conic cusps on an initially smooth surface of a perfectly conducting liquid (liquid metal) in an external electric field is analytically studied. When the singularity is formed, the apex curvature radius of the accelerating protrusion, local electric field strength, and fluid velocity become infinite in a finite time. It has been demonstrated that two scales with different types of fluid behavior can be distinguished in this process. At the nanoscale (the curvature radius of the conic apex is tens of nanometers or less; the electric field strength at the apex is about 108 V/cm and higher), viscous effects play a decisive role, and a cone with the limiting opening angle of 33.1° is formed. On the macroscopic scale (the local field strength is less than 108 V/cm for liquid metals), the ideal fluid approximation is applicable, and a cone of the opening angle 98.6° (Taylor's angle) develops. In both cases, self-similar fluid flow regimes are realized, for which the spatial scale decreases with time following the power law (t0 – t)2/3, where t0 is the blowup time. In this process, the Weber number remains practically unchanged and, according to our estimates, approximately equal to 102; at the same time, the Reynolds number decreases as (t0 – t)1/3.

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