抄録
The volume production of negative ions are discussed with particular emphasis on the extraction of negative ions from a plasma. The dominant negative ion production mechanism recently discovered is the dissociative electron attachment to highly vibrationally excited molecules. The negative ion production and extraction experiments of the multicusp, the reflex-type and the sheet plasma sources are introduced. It seems that the investigation of the electrostatic field near the plasma-sheath boundary in a magnetic field is necessary to extract the negative ions effectively as well as suppressing electrons.
