The generated thermionic electrons from the inductively heated lanthanum hexaboride hollow cathode are subsequently given sufficient energy through an accelerating voltage (AV) between the cathode and anode. This results in ionization of heavier gas atoms such as argon, separately introduced into the plasma source cathode and anode regions. Other plasma source features include axially displaced anode and cathode electrodes with decoupled magnetic fields in the anode and cathode regions, enabling separate control of the plasma ion energy, ion current density and spatial distribution within the chamber.