A hollow cathode source with a specially designed cusp magnetic field Bz(r,θ) provides clustering environment to the sputtered carbon atoms and ions. Source's distinctive features are its sooting properties that depend upon the two well-defined regions within the discharge. The cusp field drives both of these regions but in different modes – one region ionizes the source gas, introduces the sputtered C from the hollow cathode while the other is the collision dominated gyrational motion of the C+ ions along Bz(r,θ) contours. Tunability of plasma's discharge characteristics provides the tool to investigate clustering in the sooting plasma.