Vacuum-based surface engineering and coating processes require plasma sources generating a high charge carrier density in order to achieve enhanced sputter and activation effects. Fraunhofer FEP is providing a hollow-cathode based plasma source, which produces homogeneous large-volume plasmas of up to 1 m3 with maximum plasma densities of more than 1012 cm-3 at chamber pressures between 0.1 and 10 Pa. The cathode tube is flown through by the working gas such as argon with flow rates between 8 and 100 sccm. A diffuse arc discharge with currents up to 200 A between the inner cathode tube surface and the surrounding annular anode is ignited and amplified by an axial magnetic field with field strengths up to 100 mT.