Sheath structure of an electronegative plasma with cold positive ions

The one-dimensional collisionless sheath model of electropositive plasmas i s extended here to study the sheath structure of an electronegative plasma at steady state with the assumptions of cold positive ions and planar sheat h configurations, Similar to the electropositive plasma sheath, a net charg e layer is built within the sheath. However, the net charge density distrib ution within the sheath is sensitive to the plasma electronegativity (ratio of negative ion density n(-b) to the electron density n(eb)), It is most i nteresting that the sheath thickness varies nonmonotonically with the plasm a electronegativity of the bulk plasma. Last, the effects of applied wall p otential and temperature ratio of electrons to negative ions are discussed.