Editing Plasma torch (section)

===Thermal plasma DC torches, non-transferred arc, hot cathode===
[[File:Non-transferred DC plasma torch.png|upright=1.35|thumb|Cross-sectional representation of a non-transferred DC plasma torch. Showing the pointed cathode and annular anode. The inlets and outlets of the water-cooling system are labelled, note that the arc temperature can be up to 15 000°C. The plasma arc is drawn for illustration purposes only. Not to scale.]]

In a DC torch, the [[Plasma (physics)#Generation of artificial plasma|electric arc]] is formed between the [[electrodes]] (which can be made of copper, [[tungsten]], [[graphite]], silver etc.), and the thermal plasma is formed from the continual input of carrier/working gas, projecting outward as a plasma jet/flame (as can be seen in the adjacent image). In DC torches, the carrier gas can be, for example, either oxygen, nitrogen, argon, helium, air, or hydrogen;<ref name="Gomez" /> and although termed such, it does not have to be a gas (thus, better termed a carrier fluid).

For example, a research plasma torch at the Institute of Plasma Physics (IPP) in Prague, Czech Republic, functions with an [[H2O|H<sub>2</sub>O]] vortex (as well as a small addition of argon to ignite the arc), and produces a high temperature/velocity plasma flame.<ref name=Hrabovsky>{{cite journal |last=Hrabovský |first=Milan |author2=Kopecky, V.|author3= Sember, V. |author4=Kavka, T. |author5=Chumak, O. |author6=    Konrad, M. |title=Properties of Hybrid Water/Gas DC Arc Plasma Torch |journal=IEEE Transactions on Plasma Science |date=August 2006 |volume=34 |issue=4 |pages=1566–1575 |bibcode = 2006ITPS...34.1566H |doi = 10.1109/TPS.2006.878365|s2cid=36444561 }}</ref> In fact, early studies of arc stabilization employed a water-vortex.<ref>{{cite journal |last=Kavka |first=T |author2=Chumak, O. |author3=Sember, V. |author4=Hrabovsky, M. |title=Processes in Gerdien arc generated by hybrid gas-water torch |journal=28th ICPIG |date=July 2007}}</ref> Overall, the electrode materials and carrier fluids have to be specifically matched to avoid excessive electrode corrosion or oxidation (and contamination of materials to be treated), while maintaining ample power and function.

Furthermore, the flow-rate of the carrier gas can be raised to promote a larger, more projecting plasma jet, provided that the arc current is sufficiently increased; and vice versa.

The plasma flame of a real plasma torch is a few inches long at most; it is to be distinguished from [[Plasma weapon (fiction)|fictional long-range plasma weapons]].