A new DC plasmatron with a hot rod cathode and cold nozzle anode was proposed and tested at atmospheric pressure, generating nearly spectrally clean plasmas of air, air/diesel fuel mixture, oxygen, and CF4. The arc Volt-Ampere characteristic (VAC) is an integral indicator reflecting the general behavior of all the arc parts, among which the most important are the by-electrode layers and positive column. The sensitivity of the VAC to the gas flow velocity in the technologic channel confirmed the external vortex nature of the anode arc spot, which does not hide inside the anode orifice, but exits it and interacts with the gas flow. (c) 2006 Elsevier B.V. All rights reserved.