Characteristics of Positive Ions in the Sheath Region of Magnetized Collisional Electronegative Discharges  

作　　者：M.M.HATAMI A.R.NIKNAM 

机构地区：[1]Physics Department of K.N.Toosi University of Technology [2]Laser-Plasma Research Institute of Shahid Beheshti University,G.C.

出　　处：《Plasma Science and Technology》2014年第6期552-556,共5页等离子体科学和技术（英文版）

摘　　要：A hydrodynamic model is used to investigate the characteristics of positive ions in the sheath region of a low-pressure magnetized electronegative discharge. Positive ions are modeled as a cold fluid, while the electron and negative ion density distributions obey the Boltzmann distribution with two different temperatures. By taking into account the ion-neutral collision effect in the sheath region and assuming that the momentum transfer cross section has a power law dependence on the velocity of positive ions, the sheath formation criterion （modified Bohm＇s criterion） is derived and it is shown that there are specified maximum and minimum limits for the ion Mach number M. Considering these two limits of M, the behaviors of electrostatic potential, charged particle density distributions and positive ion velocities in the sheath region are studied for different values of ion-neutral collision frequency.A hydrodynamic model is used to investigate the characteristics of positive ions in the sheath region of a low-pressure magnetized electronegative discharge. Positive ions are modeled as a cold fluid, while the electron and negative ion density distributions obey the Boltzmann distribution with two different temperatures. By taking into account the ion-neutral collision effect in the sheath region and assuming that the momentum transfer cross section has a power law dependence on the velocity of positive ions, the sheath formation criterion （modified Bohm＇s criterion） is derived and it is shown that there are specified maximum and minimum limits for the ion Mach number M. Considering these two limits of M, the behaviors of electrostatic potential, charged particle density distributions and positive ion velocities in the sheath region are studied for different values of ion-neutral collision frequency.

关 键 词：electronegative plasma hydrodynamic model magnetized plasma sheath Bohm＇s criterion 

分 类 号：O562.5[理学—原子与分子物理]