NEGATIVE-IONS IN LOW-PRESSURE DISCHARGES

Several aspects of negative ions in low pressure discharges are treate d. The elementary processes, in which negative ions are produced and d estroyed, are summarized. The influence of negative ions on plasma ope ration is analyzed in terms of transport equations. It is shown that d iffusion, electric field, power input, plasma stability and plasma bou ndary layer are strongly affected by the presence of negative ions. Fi nally, an overview is given of experimental techniques for the detecti on of negative ions. Some typical results in low pressure discharges a re presented.