Attachment-dominated electron-beam-ionized discharges

In this letter we derive the stability criterion in discharges where two-step ionization is dominant. For stable equilibrium the attachment rate has to be greater than or equal to twice the ionization rate. Two-step ionization is often dominant in discharge-pumped visible lasers because of the relatively large number of electronically excited states. Analysis of the KrF laser discharge indicates that two-step ionization is dominant.