Separation of arc plasma and current in electrical arc - An initial study

The authors consider a welding arc as a composite of an electron flow and electrically neutral arc plasma consisting of equal numbers of ions and electrons. In normal welding conditions, the arc plasma and electron flow are merged forming an arc of classical definition. In this paper, the arc plasma and the electron flow that ionized the gas to form the arc plasma are considered separable. To demonstrate the arc separation phenomena, this initial study deviates the anode from the tungsten axis both for the constrained plasma arc (PA) and unconstrained free gas tungsten arc (GTA) to deviate the electron flow. An interference gas flow is also applied as an external force to deviate the arc plasma whose initial speed is approximately along the tungsten arc axis. The observed phenomena are qualitatively analyzed to show that separability is indeed a property of the welding arc. A simplified preliminary theoretical analysis shows arc separability is determined by the initial speed of the arc plasma, which in turn depends on the welding parameters. While the primary concern of this initial study is to disclose only in qualitative ways that the arc can be separated into the arc plasma and electron flow, it is also the intent of the authors to quantitatively study the separation in the future as well as to separate arcs for specific application needs.