[en] 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