Influence of the positive ion thermal motion on the stratified presheath in electronegative plasmas

As the Bohm criterion becomes multivalued in electronegative plasmas, when the ionization rate is low, the solution of Poisson's equation consists of an oscillatory electric potential profile before the sheath is formed (stratified presheath). By including the positive ion thermal motion these oscillations may be attenuated. The influence of this thermal motion on the parameter space region in which the stratified presheath takes place in the case of plane geometry is analysed.