Comparison of plasma transport theory with measurements in a discharge

This paper and its companion paper describe the comparison between a one-dimensional theoretical model of a hydrogen discharge in a magnetic multipole plasma source and experimental measurements of the plasma parameters. The discharge chamber, described here, has been designed to produce significant densities of ions by incorporating a weak transverse field through the discharge to obtain electron cooling so as to maximize production. Langmuir probes are used to monitor the plasma, determining the ion density, the electron density and temperature and the plasma potential. The negative density is measured by photo-detachment of the extra electron using an intense laser beam. The model, described in the companion paper, uses the presented source geometry to calculate these plasma quantities as a function of the major arc parameters; namely the arc current and voltage and gas pressure. Good agreement is obtained between theory and experiment as a function of position and arc parameters.