Heat flow through a plasma sheath in the presence of secondary electron emission from plasma-wall interaction

2017 ◽  
Vol 57 (2) ◽  
pp. 50-57 ◽  
Author(s):  
Jing Ou ◽  
Xiaoyun Zhao
Keyword(s):  
Heat Flow ◽  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Plasma Sheath ◽  
Flow Through ◽  
Wall Interaction

Stability of different plasma sheaths near a dielectric wall with secondary electron emission

2019 ◽  
Vol 85 (6) ◽  
Author(s):  
Shaowei Qing ◽  
Jianguo Wei ◽  
Wen Chen ◽  
Shengli Tang ◽  
Xiaogang Wang
Keyword(s):  
Electron Emission ◽  
Secondary Electron ◽  
Collisionless Plasma ◽  
Secondary Electron Emission ◽  
Plasma Sheath ◽  
Dielectric Wall ◽  
Maxwellian Plasma ◽  
Wide Range ◽  
Plasma Sheaths ◽  
Sheath Structure

The linear theory stability of different collisionless plasma sheath structures, including the classic sheath, inverse sheath and space-charge limited (SCL) sheath, is investigated as a typical eigenvalue problem. The three background plasma sheaths formed between a Maxwellian plasma source and a dielectric wall with a fully self-consistent secondary electron emission condition are solved by recent developed 1D3V (one-dimensional space and three-dimensional velocities), steady-state, collisionless kinetic sheath model, within a wide range of Maxwellian plasma electron temperature $T_{e}$ . Then, the eigenvalue equations of sheath plasma fluctuations through the three sheaths are numerically solved, and the corresponding damping and growth rates $\unicode[STIX]{x1D6FE}$ are found: (i) under the classic sheath structure (i.e. $T_{e}<T_{ec}$ (the first threshold)), there are three damping solutions (i.e. $\unicode[STIX]{x1D6FE}_{1}$ , $\unicode[STIX]{x1D6FE}_{2}$ and $\unicode[STIX]{x1D6FE}_{3}$ , $0>\unicode[STIX]{x1D6FE}_{1}>\unicode[STIX]{x1D6FE}_{2}>\unicode[STIX]{x1D6FE}_{3}$ ) for most cases, but there is only one growth-rate solution $\unicode[STIX]{x1D6FE}$ when $T_{e}\rightarrow T_{ec}$ due to the inhomogeneity of sheath being very weak; (ii) under the inverse sheath structure, which arises when $T_{e}>T_{ec}$ , there are no background ions in the sheath so that the fluctuations are stable; (iii) under the SCL sheath conditions (i.e. $T_{e}\geqslant T_{e\text{SCL}}$ , the second threshold), the obvious ion streaming through the sheath region again emerges and the three damping solutions are again found.

Surface effects in a capacitive argon discharge in the intermediate pressure regime

2021 ◽  
Author(s):  
Jon Tomas Gudmundsson ◽  
Janez Krek ◽  
De-Qi Wen ◽  
Emi Kawamura ◽  
Michael A Lieberman
Keyword(s):  
Excited States ◽  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Plasma Sheath ◽  
Secondary Electrons ◽  
Particle In Cell ◽  
Argon Discharge ◽  
Discharge Operation ◽  
Ion Impact

Abstract One-dimensional particle-in-cell/Monte Carlo collisional (PIC/MCC) simulations are performed on a capacitive 2.54 cm gap, 1.6 Torr argon discharge driven by a sinusoidal rf current density amplitude of 50 A/m2 at 13.56 MHz. The excited argon states (metastable levels, resonance levels, and the 4p manifold) are modeled self-consistently with the particle dynamics as space- and time-varying fluids. Four cases are examined, including and neglecting excited states, and using either a fixed or energy-dependent secondary electron emission yield due to ion and/or neutral impact on the electrodes. The results for all cases show that most of the ionization occurs near the plasma-sheath interfaces, with little ionization within the plasma bulk region. Without excited states, secondary electrons emitted from the electrodes are found to play a strong role in the ionization process. When the excited states, secondary electron emission due to neutral and ion impact on the electrodes are included in the discharge model, the discharge operation transitions from α-mode to γ-mode, in which nearly all the ionization is due to secondary electrons. Excited states are very effective in producing secondary electrons, with approximately 14.7 times the contribution of ion bombardment. Electron impact of ground state argon atoms by secondary electrons contributes about 76 % of the total ionization; primary electrons, about 11 %; metastable Penning ionization, about 13 %; and multi-step ionization, about 0.3 %.

scholarly journals Effects of q-nonextensive distribution of electrons on secondary electron emission in plasma sheath

2019 ◽  
Vol 68 (18) ◽  
pp. 185204
Author(s):  
Xiao-Yun Zhao ◽  
Bing-Kai Zhang ◽  
Chun-Xiao Wang ◽  
Yi-Jia Tang
Keyword(s):  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Plasma Sheath ◽  
Nonextensive Distribution

Plasma–wall interaction inside a Hall thruster

2002 ◽  
Vol 68 (4) ◽  
pp. 305-319 ◽  
Author(s):  
SUBRATA ROY ◽  
B. P. PANDEY
Keyword(s):  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Ionization Rate ◽  
Electron Velocity ◽  
Hall Thruster ◽  
Third Order ◽  
Order Polynomial ◽  
Sputter Yield ◽  
Wall Interaction

The dynamics of a Hall thruster is investigated numerically in the presence of a plasma–wall interaction. The plasma–wall interaction is a function of the wall potential, which in turn is determined by the secondary electron emission and sputtering yield. In the present work, the effect of secondary electron emission and sputter yield have been considered simultaneously. Owing to disparate temporal scales, ions and neutrals have been described by a set of time-dependent equations while electrons are considered in a steady state. Based on the experimental observations, a third-order polynomial in electron temperature is used to calculate the ionization rate. The changes in the plasma density, potential and azimuthal electron velocity due to the sputter yield are significant in the acceleration region. The change in ion and electron velocity and temperature is small. The neutral velocity, which decreases initially, starts increasing towards the exit consistent with the computed neutral density profile. The results are qualitatively compared with the experiments.

Effects of secondary electron emission from a floating surface on the plasma sheath

Vacuum ◽  
2004 ◽  
Vol 73 (1) ◽  
pp. 89-92 ◽  
Author(s):  
Francesco Taccogna ◽  
Savino Longo ◽  
Mario Capitelli
Keyword(s):  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Plasma Sheath ◽  
Floating Surface
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