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由于缺乏详细的理论计算和实验结果, 在研究绝缘壁面稳态流体鞘层特性时, 通常假设壁面出射的总二次电子服从单能分布( 0)、半Maxwellian分布等. 在单能电子轰击壁面的详细二次电子发射模型基础上, 采用Monte Carlo方法统计发现: 当入射电子服从Maxwellian分布时, 绝缘壁面发射的总二次电子服从三温Maxwellian分布. 进而, 采用一维稳态流体鞘层模型进行对比研究, 结果表明: 二次电子分布函数对鞘边离子能量、壁面电势、电势及电子/离子密度分布等均具有明显影响; 总二次电子服从三温Maxwellian分布时, 临界空间电荷饱和鞘层无解, 表明随着壁面总二次电子发射系数的增加, 鞘层直接从经典鞘层结构过渡到反鞘层结构.
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关键词:
- 鞘层 /
- 二次电子分布函数 /
- Monte Carlo模拟
It is widely known that the energy distribution of secondary electrons induced by a single-energy electron beam presents typical bimodal configuration. However, the total velocity distribution of secondary electrons induced by a Maxwellian plasma electron group has not been revealed clearly, due to the lack of detailed theoretical calculation and calculation and experiment result. Therefore, researchers usually function satisfies single-energy distribution ( 0), half-Maxwellian distribution and so on, in order to study the characteristics of stable fluid sheath near a dielectric wall. For this reason, using the Monte Carlo method to simulate the wall secondary electron emission events based on a detailed probabilistic model of secondary electron emission induced by single-energy incident electron beam, we found that, when the incident electron follows an isotropic Maxwellian distribution, the total perpendicular-to-wall velocity distribution of the secondary electrons emitted from dielectric wall follows a three-temperature Maxwellian distribution. In the simulation, the incident angle of the plasma electrons and the emergence angle of the secondary electrons are considered, so the Monte Carlo method can discriminate whether the secondary electron velocity is perpendicular to or parallel to the wall surface. Then, a one-dimensional stable fluid sheath model is established under the wall boundary condition that the secondary electrons obey the three-temperature Maxwellian distribution; and some contrastive studies are made in order to reveal the effect of wall total secondary electron distribution functions such as single-energy distribution, half-Maxwellian distribution, and three-temperature Maxwellian distribution with the sheath characteristics. It is found that the total secondary electron distribution function can significantly influence the ion energy at the sheath interface, the wall surface potential, the potential and electron/ion-density distributions, and so on. Both the ion energy at sheath interface and the wall surface potential increase monotonously with the increase of wall total secondary electron emission coefficient. But the values of three-temperature Maxwellian distribution differ much from that of half-Maxwellian distribution and single-energy distribution. When the total secondary electron follows a three-temperature Maxwellian distribution, the critical space charge saturated sheath has no solution, indicating that with the increase of the wall total secondary electron emission coefficient, the sheath will directly transit from the classic sheath structure to the anti-sheath one. In the future work, a kinetic, static sheath model will be developed in order to study the characteristics of anti-sheath and space charge saturated sheath near a dielectric wall[1] Raitses Y, Staack D, Keidar M, Fisch N J 2005 Phys. Plasmas 12 057104
[2] Mazouffre S, Echegut P, Dudeck M 2007 Plasma Sources Sci. Technol. 16 13
[3] Raitses Y, Ashkenazy J, Appelbaum G 1997 25th International Electric Propulsion Conference (Cleveland, OH: Electric Rocket Propulsion Society) Paper No. IEPC 97-056
[4] Ahedo E, Gallardo J M, Martinez-Sanchez M 2003 Phys. Plasmas 10 3397
[5] Takamura S, Ohno N, Ye M Y, Kuwabara T 2004 Contrib. Plasma Phys. 44 126
[6] Campanell M D, Wang H, Kaganovich I D, Khrabrov A V 2015 Plasma Sources Sci. Technol. 24 034010
[7] Qing S W, Yu D R, Wang X G, Duan P 2011 J. Propul. Technol. 32 813
[8] Qing S W, Li H, Wang X G, Song M J, Yu D R 2012 EPL 100 35002
[9] Qing S W, E P, Duan P 2013 Acta Phys. Sin. 62 055202 (in Chinese) [卿绍伟, 鄂鹏, 段萍 2013 物理学报 62 055202]
[10] Zhao X Y, Liu J Y, Duan P, Li Z X 2011 Acta Phys. Sin. 60 045205 (in Chinese) [赵晓云, 刘金远, 段萍, 倪致祥 2011 物理学报 60 045205]
[11] Liu J Y, Chen L, Wang F, Wang N, Duan P 2010 Acta Phys. Sin. 59 8692 (in Chinese) [刘金远, 陈龙, 王丰, 王南, 段萍 2010 物理学报 59 8692]
[12] Hobbs G D, Wesson J A 1967 Plasma Phys. 9 85
[13] Xue Z H, Zhao X Y, Wang F, Liu J Y, Liu Y, Gong Y 2009 Plasma Sci. Technol. 11 57
[14] Morozov A I, Savelyev V V 2001 Reviews of Plasma Physics (Volume 21) (New York: New York Consultants Bureau) p241
[15] Furman M A, Pivi M T F 2002 Phys. Rev. ST Accel. Beams 5 124404
[16] Taccogna F, Longo S, Capitelli M 2005 Phys. Plasmas 12 093506
[17] Ordonez C A 1992 Phys. Fluids B 4 778
[18] Schwager L A 1993 Phys. Fluids B 5 631
[19] Langendorf S, Walker M 2015 Phys. Plasmas 22 033515
[20] Rizopoulou N, Robinson A P L, Coppins M, Bacharis M 2014 Phys. Plasmas 21 103507
[21] Herring C, Nichols M H 1949 Rev. Mod. Phys. 21 185
[22] Morozov A I, Savelyev V V 2004 Plasma Phys. Rep. 30 299
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[1] Raitses Y, Staack D, Keidar M, Fisch N J 2005 Phys. Plasmas 12 057104
[2] Mazouffre S, Echegut P, Dudeck M 2007 Plasma Sources Sci. Technol. 16 13
[3] Raitses Y, Ashkenazy J, Appelbaum G 1997 25th International Electric Propulsion Conference (Cleveland, OH: Electric Rocket Propulsion Society) Paper No. IEPC 97-056
[4] Ahedo E, Gallardo J M, Martinez-Sanchez M 2003 Phys. Plasmas 10 3397
[5] Takamura S, Ohno N, Ye M Y, Kuwabara T 2004 Contrib. Plasma Phys. 44 126
[6] Campanell M D, Wang H, Kaganovich I D, Khrabrov A V 2015 Plasma Sources Sci. Technol. 24 034010
[7] Qing S W, Yu D R, Wang X G, Duan P 2011 J. Propul. Technol. 32 813
[8] Qing S W, Li H, Wang X G, Song M J, Yu D R 2012 EPL 100 35002
[9] Qing S W, E P, Duan P 2013 Acta Phys. Sin. 62 055202 (in Chinese) [卿绍伟, 鄂鹏, 段萍 2013 物理学报 62 055202]
[10] Zhao X Y, Liu J Y, Duan P, Li Z X 2011 Acta Phys. Sin. 60 045205 (in Chinese) [赵晓云, 刘金远, 段萍, 倪致祥 2011 物理学报 60 045205]
[11] Liu J Y, Chen L, Wang F, Wang N, Duan P 2010 Acta Phys. Sin. 59 8692 (in Chinese) [刘金远, 陈龙, 王丰, 王南, 段萍 2010 物理学报 59 8692]
[12] Hobbs G D, Wesson J A 1967 Plasma Phys. 9 85
[13] Xue Z H, Zhao X Y, Wang F, Liu J Y, Liu Y, Gong Y 2009 Plasma Sci. Technol. 11 57
[14] Morozov A I, Savelyev V V 2001 Reviews of Plasma Physics (Volume 21) (New York: New York Consultants Bureau) p241
[15] Furman M A, Pivi M T F 2002 Phys. Rev. ST Accel. Beams 5 124404
[16] Taccogna F, Longo S, Capitelli M 2005 Phys. Plasmas 12 093506
[17] Ordonez C A 1992 Phys. Fluids B 4 778
[18] Schwager L A 1993 Phys. Fluids B 5 631
[19] Langendorf S, Walker M 2015 Phys. Plasmas 22 033515
[20] Rizopoulou N, Robinson A P L, Coppins M, Bacharis M 2014 Phys. Plasmas 21 103507
[21] Herring C, Nichols M H 1949 Rev. Mod. Phys. 21 185
[22] Morozov A I, Savelyev V V 2004 Plasma Phys. Rep. 30 299
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