 Processing plasmas are typically operated at pressures of a few millitorr to a few torr, although arc discharges and inductive plasmas can be ignited at atmospheric pressure.Plasmas with low fractional ionization are of great interest for materials processing because electrons are so light, compared to atoms and molecules, that energy exchange between the electrons and neutral gas is very inefficient.Therefore, the electrons can be maintained at very high equivalent temperatures – tens of thousands of kelvins, equivalent to several electronvolts average energy—while the neutral atoms remain at the ambient temperature.