Optimum current densities from high current H(sup (minus)) and D(sup (minus)) sources

摘要

The tandem system, with the electron energy distribution arranged spatially and with electron energies decreasing toward the exit aperture, will generate a five-fold enhancement in extracted current density when compared to an optimal single-chamber system. With the increased understanding of the underlying atomic processes, together with a body of experience in the operation high-power hydrogen and deuterium discharges, it has now become possible to specify in absolute terms the optimal current-density performance of a hydrogen/deuterium system. A variation on the single-chamber and tandem systems has been purposed that employs a single-chamber, pulsed discharge. Following the discharge pulse, the transient variation of the electron energy distribution allows for a more optimal generation of negative ions than does the static single-chamber system. Some of the limitations of this system when compared with the steady-state tandem system are discussed here.