Using the total voltage drop of a stabilized DC arc to assess plasma parameters

Direct current arc plasma that is used as an excitation source in analytical spectroscopy in different industrial areas has been discussed on the basis of plasma physics. A study was made into the voltage–current characteristics of a DC argon arc during the consumption of various amounts of potassium, as EIE, in the current range from 3 to 10 A. Records of voltage drops across a direct current (DC) arc carry direct evidence of the changes that take place in the plasma seeded with Easily Ionizable Elements (EIE). Voltage–current behavior, as well as some spectral characteristics of such plasma were combined, and used to assess plasma parameter changes. The goal was to correlate the recorded voltage with plasma parameters. There is a critical concentration of KCl in the sprayed solution that causes the highest voltage jump and, consequently, the fastest temperature drop and electron number density growth.