Modulation of uniform magnetic field on electron dynamics in low‐pressure capacitively coupled plasmas

The electron dynamics in uniform magnetized capacitively coupled plasmas are investigated by using a one‐dimensional particle‐in‐cell simulation with a Monte Carlo collision model. It is found that the nonlinear dynamic behaviors of electrons are slightly modulated at weak magnetic fields, with more electron beams appearing during one sheath expansion. The electron beams are reversed before reaching the opposite electrode at moderate magnetic fields under the effect of Lorentz force. The discharge becomes very localized at very high magnetic fields, as the energetic electrons are confined in the vicinity of the sheath edge. The nonlocal to local transition of discharge characteristics is induced at different magnetic fields for various discharge frequencies. Generally, the discharge transition happens at stronger magnetic fields for high‐discharge frequencies. A quantitative relation between the discharge frequency and cyclotron frequency is given for the discharge transition. This study adequately studied the spatiotemporal electron dynamics and complex physical mechanisms in magnetized radiofrequency discharges. The discharge characteristics are demonstrated to be distinct at various magnetic fields. When the magnetic field is small, the energetic electrons can travel across a large range to enhance the discharge, which corresponds to the nonlocal discharge regime at low pressure. In contrast, the energetic electrons are well confined in the vicinity of the sheath edge due to the reduced cyclotron radius at strong magnetic fields. The interactions between the electrons and sheath become so fierce, that the power deposition mainly locates at the sheath edge, indicating a discharge transition to the local regime. The nonlocal to local transition of discharge characteristics is induced at different magnetic fields for various discharge frequencies. Generally, the discharge transition happens at stronger magnetic fields for high‐discharge frequencies. A quantitative relation between the discharge frequency and cyclotron frequency is given for the discharge transition.