Experimental and theoretical results on effect of multi-step ionization on total energy loss in an argon inductive discharge

The change of total energy loss ($\varepsilon_{\mbox{T}} )$ with electron temperature was analyzed by a global model considering multi-step ionization in the argon inductive discharge. As pressure increases, collisional energy loss ($\varepsilon_{\mbox{c}} )$ increases but mean kinetic energy lost per ion lost ($\varepsilon_{\mbox{i}} )$ and mean kinetic energy lost per electron lost ($\varepsilon_{\mbox{e}} )$ decrease. Therefore, there is a pressure that $\varepsilon_{\mbox{T}} $ becomes minimum and its corresponding electron temperature is present. When $\varepsilon_{\mbox{T}} $ is minimized at certain pressure and electron temperature, the plasma is more efficiently generated and the density is maximized. The $\varepsilon _{\mbox{c}} $ considered the multi-step ionization is lower than the unconsidered case. It can be predicted that there will be a minimum value of $\varepsilon_{\mbox{T}} $ at lower electron temperature. In this work, we studied the effect of multi-step ionization on the electron temperature where $\varepsilon_{\mbox{T}} $ is the minimum. For each condition, the electron temperature and the plasma density were measured and the total energy loss $\varepsilon_{\mbox{T}} $ was obtained through these measured values.