Electron sheaths near a positively biased plate subjected to a weak electron beam  

作　　者：刘琦 卫子安 马锦秀 弋开阳 陶万 李政元 Qi LIU;Zian WEI;Jinxiu MA;Kaiyang YI;Wan TAO;Zhengyuan LI(School of Physical Sciences,University of Science and Technology of China,Hefei 230026,Peopleʼs Republic of China;Department of Plasma Physics and Fusion Engineering,University of Science and Technology of China,Hefei 230026,Peopleʼs Republic of China;Southwestern Institute of Physics,Chengdu 610041,Peopleʼs Republic of China)

机构地区：[1]School of Physical Sciences,University of Science and Technology of China,Hefei 230026,Peopleʼs Republic of China [2]Department of Plasma Physics and Fusion Engineering,University of Science and Technology of China,Hefei 230026,Peopleʼs Republic of China [3]Southwestern Institute of Physics,Chengdu 610041,Peopleʼs Republic of China

出　　处：《Plasma Science and Technology》2023年第3期70-77,共8页等离子体科学和技术（英文版）

基　　金：supported by National Natural Science Foundation of China(Nos.11975229 and 11705201)。

摘　　要：Electron sheaths have previously only been measured near a positively biased small electrode, in which a potential dip was often observed. In this paper, we present an experimental study on the electron sheath near a stainless steel plate in the presence of a weak electron beam. It is shown that the electron beam, though its density is much lower than that of the background plasma, will substantially alter the sheath structure, i.e., it causes the disappearance of the potential dip when the beam energy just exceeds the ionization potential of the neutral gas but later enhances the dip for higher energies. It is also shown that proper biases on the plate and chamber wall are the key to the formation of the electron sheath and the dip. For a fixed plate bias but with different electron beam energy, the measured thickness of the ion-free Child–Langmuir sheath agrees well with that of the theoretical model.

关 键 词：electron sheath potential dip electron-beam-plasma system 

分 类 号：O53[理学—等离子体物理]