Double Sheath Associated with Negative Ion Extraction from a Plasma Containing Negative Ions

摘要

The double sheaths formed by plasmas that contain thermal electrons, as well as positive and negative ions has been investigated. The negative ion beam that can be extracted under these conditions is given as a function of the electric potential, the density ratio and the Langmuir limit. The result is useful when if conies to extract ion beams from negative ion sources.