Current limiting properties of an expanding helical arc

The expansion of an arc of helical form is governed by both electromagnetic and aerodynamic forces, themselves functions of the arc current and electric field strength through complex interactions. In attempting to describe the arc´s expansion the product of these two quantities, the power input, can be usefully exploited. As the arc´s helical length increases, the arc voltage builds up until it opposes the driving voltage, leading to current limitation and interruption. Experimental results showing the evolution of electric field strength with current arc also presented