Effect of nanoparticles on an rf discharge afterglow

The influence of nanoparticles on a discharge plasma afterglow in argon is studied using particle-in-cell Monte Carlo collision simulations. The anomalous electron density increase observed in the experiment (Berndt et al 2006 Plasma Sources Sci. Technol. 15 18) is analysed on the basis of the electron and ion distribution functions. It is shown that the departure of fast electrons to the electrodes in the early afterglow is responsible for the rapid increase in the electron density. When the fast electrons escape from the discharge volume, the balance of the electron and ion currents on the dust surface is disturbed, and the magnitude of the dust floating potential drops. The electrons released from the dust surface contribute to the anomalous growth of the electron density. The additional production of electrons due to metastable-metastable ionization enhances the effect of electron density increase provided by dust discharging.