Global visualization of powder trapping in capacitive RF plasmas by two-dimensional laser scattering

Understanding particle dynamics requires comparison of spatially resolved measurements with two-dimensional (2-D) simulations. In this work, a cross section of a capacitive discharge is illuminated with an expanded laser beam, and global scattered light is recorded by camera. Plasma equipotentials are visualized using the scattered intensity from a small amount of particles trapped in an argon plasma. At low RF voltages, good agreement is found with 2-D fluid simulations, whereas displacement of the power clouds toward the sheaths is observed at high voltage.