Electron Dynamics in Asymmetric CCRF Plasmas: From Fundamental Principles to Simulation Insights

Capacitively coupled radio frequency (CCRF) discharges operated in geometrically asymmetric configurations exhibit a range of distinct physical effects that strongly influence electron heating, sheath dynamics, and discharge symmetry. In this work, we investigate the time-resolved electron dynamics in a discharge with coaxial electrode configuration using 1D3V particle-in-cell/Monte Carlo collision (PIC/MCC) simulations.

Our analysis covers the low-pressure operation regime, where the asymmetry between powered and grounded electrode areas leads to a self-generated DC bias and asymmetric sheath behavior. We show how the coupling of electron motion to the oscillating sheath electric fields gives rise to characteristic energy distributions, spatial transport patterns, and transient field reversals. Specific attention is given to the role of geometric asymmetry in shaping nonlinear electron heating mechanisms and controlling the temporal and spatial characteristics of the power deposition.

The results provide insight into fundamental mechanisms governing asymmetric CCRF discharges and serve as a reference for reduced fluid models and advanced plasma process design.