Langmuir probe study in the post-discharge of a pulsed helicon discharge

The study of a pulsed helicon discharge with a planar Langmuir probe is presented. An unexpected and unreported effect has been observed, i.e. a large current peak on the probe at the end of the pulse. The post-discharge has then been carefully studied and the temporal evolution of the plasma parameters during the pulsed discharge was obtained by analysing the probe characteristics. In the post-discharge, a relaxation of the plasma parameters (plasma density (ne), plasma potential (Vp), electron temperature (Te)) was observed. The difference between the decay times measured for each parameter enables one to explain the current peak on the probe at the beginning of the post-discharge.