PIC/MC modeling of dusty radio-frequency discharges

We have extended a one-dimensional particle-in-cell plus Monte Carlo model for argon radio-frequency discharges with scattering and capture of electrons and ions on dust particles immersed in the discharge. The orbital motion limited cross section is used for the capture process. For scattering, we took the bare Coulomb interaction for impact parameters below the linearized Debye length and neglected the interaction for larger values, thus accounting for the shielding. With this model, we have studied discharges with dust confined in two layers, leaving a dust-free void in the center and dust-free sheaths in front of the electrodes. This situation resembles the distribution along the axis of discharges studied in microgravity plasma crystal experiments. Results show the generation of (multiple) space charge layers near the edges of the dust clouds and the interdependence of the dust charge and the electron energy distribution function (EEDF), in particular the EEDF in the central void. Also, higher harmonics in the current waveform, frequently used to diagnose dusty plasmas, are observed.