Effective degree of ionization

The degree of ionization in the plasma tells you how much of the gas is actually split into ions and electrons. It depends strongly on temperature – the hotter, the more particles are ionized. In welding this is important because the degree of ionization determines the electrical conductivity of the plasma. If it's too low, the arc ignites poorly and runs erratically. If it's too high, the plasma becomes unstable and hard to control. In practice you notice this in the behavior of the arc – you have to set the parameters so that it burns steadily and consistently.