Optimum extracted H− and D− current densities from gas-pressure-limited high-power hydrogen/deuterium tandem ion sources

The tandem hydrogen/deuterium ion source is modeled for the purpose of identifying the maximum current densities that can be extracted subject to the gas-pressure constraints proposed for contemporary beam-line systems. Optimum useful extracted current densities are found to be in the range of approximately 7–10 mA cm−2. The sensitivity of these current densities is examined subject to uncertainties in the underlying atomic/molecular rate processes. A principal uncertainty remains the quantification of the molecular vibrational distribution following H+3 wall collisions.