The electron density stabilisation process in pulsed surface wave plasmas

The authors present an experimental study of the evolution of electron density during the formation process of a plasma column produced by a surface wave. The experiments have been performed in argon gas, using pulsed microwave power at 2.45 GHz, in the 0.3-30 Torr pressure range. The time elapsed between the arrival of the ionisation front at a given axial position and the moment the electron density reaches 90% of its stationary value (stabilisation time) has been determined. This stabilisation time increases exponentially with axial position towards the end of the plasma column, as the power of the surface wave decreases.