Direct-current plasma (DCP) is a type of plasma source used for atomic emission spectroscopy that utilizes three electrodes to produce a plasma stream. The most common three-electrode DCP apparatus consists of two graphite anode blocks and a tungsten cathode block arranged in an inverted-Y arrangement.  An argon gas source is situated between the anode blocks and argon gas flows through the anode blocks. The plasma stream is produced by briefly contacting the cathode with the anodes. Temperatures at the arc core exceed 8000 K. This three-electrode arrangement is illustrated in Figure 1.