Towards the creation of an inverse electron distribution function in two-chamber inductively coupled plasma discharges

The work continues the studies on searching for plasma media with inverse electron energy distribution function (EEDF) and providing recommendations for setting up subsequent experiments. The inverse EEDF is a distribution function that increases with increasing the energy at zero electron energy. The inverse EEDF plays a central role in the problem of negative conductivity. Based on the previously obtained criterion for the formation of an inverse EEDF in a spatially inhomogeneous plasma, a heuristic method is proposed that allows one to avoid resource-intensive calculations for spatially two-dimensional (2D) kinetic modeling on a large array of different glow discharges. It is shown that the conditions for EEDF inversion can be realized in two-chamber discharge structures due to violating the known Boltzmann distribution for electron density. The theoretical conclusions are validated by numerical modeling of low-pressure two-chamber inductively coupled plasma (ICP) discharges in the COMSOL Multiphysics environment. As a result, areas of conditions with inverse EEDF were found for subsequent detailed kinetic analysis and experimental studies.