Numerical Simulation of Ion Current Absorption by Cylindrical Langmuir Probe in Plasma Sheath
Author(s): Li Wenqiu, Wang Gang, Xiang Dong, Su Xiaobao, Institute of Electronics, Chinese Academy of Sciences, University of Chinese Academy of Sciences
Pages: 1271-1278
Year: 2016 Issue: 11
Journal: Vacuum Science and Technology
Keyword: Amendment Bohm current; Plasma sheath; Ion current; Cylindrical probe;
Abstract: Here,we systematicallyaddressed the impact ofthecylindrical Langmuir probe’s radius on plasma diagnosis and potential distribution in plasma sheath. The key variables,including the amendment Bohn current around the probe,potential distributions in plasma sheath and probe’s absorption ion currents predicted by OML,ABR and BRL theories,respectively,were numerically simulated with the non-thermal equilibrium ion absorption model of cylindrical Langmuir probe. The simulated results show that the validity of OML,ABR and BRL theories significantly depends on the probe’s radius and plasma behavior. For example,when the probe’s radius lies in 1 ~3 Debye-length,OML,ABR and BRL theories predict almost the same normalized ion currents( or plasma density);the electron temperature and plasma density strongly affect the sheath space potential distribution calculated by ABR theory; and,an ion temperature,lower than 10% electron temperature,little influences the sheath potential distribution evaluated in ABR theory.
Pages: 1271-1278
Year: 2016 Issue: 11
Journal: Vacuum Science and Technology
Keyword: Amendment Bohm current; Plasma sheath; Ion current; Cylindrical probe;
Abstract: Here,we systematicallyaddressed the impact ofthecylindrical Langmuir probe’s radius on plasma diagnosis and potential distribution in plasma sheath. The key variables,including the amendment Bohn current around the probe,potential distributions in plasma sheath and probe’s absorption ion currents predicted by OML,ABR and BRL theories,respectively,were numerically simulated with the non-thermal equilibrium ion absorption model of cylindrical Langmuir probe. The simulated results show that the validity of OML,ABR and BRL theories significantly depends on the probe’s radius and plasma behavior. For example,when the probe’s radius lies in 1 ~3 Debye-length,OML,ABR and BRL theories predict almost the same normalized ion currents( or plasma density);the electron temperature and plasma density strongly affect the sheath space potential distribution calculated by ABR theory; and,an ion temperature,lower than 10% electron temperature,little influences the sheath potential distribution evaluated in ABR theory.
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