Embodiments of the present disclosure provide apparatus and methods for improving plasma uniformity around edge regions and/or reducing non-symmetry in a plasma processing chamber. One embodiment of the present disclosure provides a plasma tuning assembly having one or more conductive bodies disposed around an edge region of a substrate support in a plasma processing chamber. The one or more conductive bodies are isolated from other chamber components and electrically floating in the processing chamber near the edge region without connecting to active electrical potentials. During operation, when a plasma is maintained in the plasma processing chamber, the presence of the one or more conductive bodies affects the plasma distribution near the one or more conductive bodies.