Characterization of an RF-driven plasma ion source for heavy ion fusion

We are testing a high-current-density high-brightness Argon-Ion Source for Heavy Ion Fusion applications. The 100-kV 20-{micro}s source has produced up to 5 mA of Ar{sup +} in a single beamlet. The extraction current density is 100 mA/cm2. We have measured the emittance of the beamlet, and the fraction of Ar{sup ++} ions under several operating conditions. We present measurements of the extracted current density as a function of RF power and gas pressure ({approx} 2 mT), current density uniformity, and energy dispersion (due to charge exchange). We are testing a 80-kV 61-hole multi-beamlet array that will produce a total current > 200 mA. In the current experiments the beamlets are not merged into a single beam. A 500-kV experiment where the beamlets will be merged to a produce 0.5-A beam is being planned.