Speaker: Prof. Jean Paul Allain, University of Illinois at Urbana-Champaign
Abstract: Although progress has been made in the last half-decade in establishing an understanding of plasma-material interactions (PMI), there remain critical knowledge gaps, particularly predicting the behavior at the plasma-material interface under reactor-relevant fusion plasma conditions in a future plasma-burning neutron-dominated environment. At this interface, high particle and heat flux from the fusion plasma can limit the material’s lifetime and reliability and therefore hinder operation of the fusion device. This region is critical to operation of a nuclear fusion reactor since material can be emitted both atomistically (e.g. through evaporation, sputtering, etc.) and/or macroscopically (i.e. during transients events, such as disruptions or edge localized modes). The environmental conditions at the plasma-material interface of a future nuclear fusion reactor interacting will be extreme. The incident plasma will carry heat fluxes of the order of 100’s of MWm-2 and particle fluxes that can average 1024 m-2s-1. The fusion reactor wall would need to operate at high temperatures near 800 C and the incident energy of particles will vary from a few eV ions to MeV neutrons. Another challenge is the management of damage over the course of time. Operating at reactor-relevant conditions means the wall material would need to perform over the course of not just seconds or minutes (i.e. as in most advanced fusion devices today and in the near-future), but from months to years. Some promising breakthrough concepts have been considered such as liquid walls and low-recycling regimes that may address both radiation damage and the impact on the interaction with the plasma edge and ultimately plasma core. This talk will focus on outlining both the challenges and promises of PMI research in nuclear fusion today and the prospects for possible solutions for future plasma-burning fusion reactors. The talk will in part summarize the recent DOE Fusion Energy Sciences Workshop on Plasma-Material Interactions and also highlight some of the recent work in Prof. Allain’s RSSEL group at UIUC.