Can we achieve the inverse sheath in tokamak plasmas? Redefining the paradigm for plasma-wall interaction in future thermonuclear reactors Project ID: GA25-17841S Provider: Czech Science Foundation Period: Jan 01, 2025 - Dec 31, 2027 Principal Investigator: Mgr. Michael Komm Ph.D. Co-investigators A. Podolník, D. Tskhakaya, J. Hečko, J. Cavalier Aims of the project: Since the dawn of plasma physics research, it has been assumed that the plasma potential should be decreasing towards a floating wall, either monotonically (Debye sheath) or with a virtual cathode (space-charge limited sheath). Recently, a new regime dubbed inverse sheath has been proposed in case of strongly emitting walls and presence of charge exchange collisions, featuring increasing potential towards the wall. In this project, we aim to study the feasibility and the properties of this regime in the conditions relevant to magnetically confined high temperature plasmas. The achievement of inverse sheath in future thermonuclear reactors could have far reaching consequences for our understanding of physics processes occurring in the plasma boundary. We plan to use state-of-art particle-in-cell and fluid modeling to demonstrate the access and stability of this regime when all relevant plasma processes are taken into account.