Electron dynamics in magnetized technological plasmas: A kinetic description

Many advanced thin-film deposition processes like HIPIMS (High Power Impulse Magnetron Sputtering) or PIAD (Plasma-Ion Aided Deposition) employ magnetized plasmas at a pressure range of 0.1 to 1 Pa and a magnetic field of 10 to 100 mT. In such plasmas, the electron gyration radius $r_{\rm L}$ is of the order of a millimeter, whereas the mean free path $\lambda$ is much larger, typically comparable with the plasma source dimension $L$ itself (some tens to hundreds of millimeters). It is generally acknowledged that in this regime fluid dynamics fails and a kinetic approach is required. This work employs the smallness of the parameter epsilon $r_{\rm L}/\lambda \sim r_{\rm L}/L$ to reduce the complexity of that approach to a tractable level. As an application, the phenomenon of spoke formation in HIPIMS discharges is addressed.