Generation of cold electrons in a low-pressure rf capacitive discharge as an analogue of a thermal explosion

Theoretical analysis of the formation of a two-temperature electron distribution function in a low-pressure rf capacitive discharge is presented. The transition to a peaked profile of the electron distribution function as the current increases is studied. Calculations and experiments show that, as the current increases, a radical rearrangement of the electron distribution accompanied by the formation of a two-temperature distribution function can occur. As a result, the average electron energy strongly decreases. For a current density above the critical value, a steady-state solution can be obtained only if electron-electron collisions are taken into account. The transition mechanism is similar to that for a thermal explosion.