The project „Electron heating in capacitive RF plasmas based on moments of the Boltzmann equation: From fundamental understanding to predictive control“ funded by the DFG started in June 2020. The project aims to fundamentally understand electron power absorption in capacitively coupled plasma sources (CCPs).

Electron power absorption (or, traditionally, electron heating), i.e. the way electrons gain / lose their energy by interacting with a space- and time dependent electric field and other particles present in the plasma (through collisions), is a fundamentally important question in low temperature plasma physics. Due to the numerous industrial and biological applications of CCPs, a better understanding of electron power absorption would be absolutely crucial for (energetically) optimizing and gaining better process control in these plasma sources.

Due to the complexity of the problem, an analytical approach is no longer feasible: therefore, the work at RUB focuses on Particle-In-Cell/Monte-Carlo-Collisions simulations, a self-consistent kinetic simulation method, that is used to simulate CCPs. Using an analysis based on the first velocity moment equation of the Boltzmann equation, the spatio-temporally resolved power absorption of the electrons can be computed and divided into different “terms”, each of which corresponds to a given physical mechanism. This gives a full, self-consistent description of power absorption. The goal of the project is to understand the role of each of these mechanisms and their hierarchy under different conditions (low / atmospheric pressure, various excitations, etc.), and based on this knowledge, make predictions about how a given plasma source might be better optimized.