A critical area of ongoing research in magnetic confinement fusion devices, such as tokamaks and stellarators, is understanding the physics of the plasma boundary and its interactions with plasma-facing components (PFCs), typically in the form of divertors or limiters.
For a fusion reactor to be viable, it must have a robust boundary solution that addresses several key challenges simultaneously: managing power exhaust to keep wall heat loads within material limits, ensuring efficient removal of fusion ash by maintaining sufficient neutral pressure for pumping, minimizing the sputtering of high-Z impurities (e.g. tungsten), and reducing fuel retention by limiting tritium trapping in wall materials—all while sustaining high plasma performance for optimal energy gain.
Plasma-material interactions encompass a variety of complex processes, including sputtering, ion implantation, radiation damage, erosion, deposition, and material re-deposition.
Wall conditioning in magnetic confinement fusion devices serves to manage impurities and control the fuel gas from PFCs.
Nonetheless, for long-pulse, next-step fusion devices, alternative strategies are being explored due to the limitations of GDB.