On the dynamic plasma-wall interactions *

The physics of edge plasmas in magnetic confinement devices is very multifaceted and complex. It involves classical and anomalous plasma transport, atomic physics of hydrogenic species and different impurities, and plasma interactions with material surfaces of plasma facing components including the first wall and divertor targets [1].

            Till recently plasma-material interactions in most cases were described by some prescribed particle and energy reflection coefficients of the ions impinging onto material surface. However, in practice these coefficients depend on many dynamic factors including the constituency of the wall material, which is usually altered by the particle species trapped in the material, surface morphology, temperature, etc. Taking these dynamic effects into account allowing describing dynamic feedback effects of the wall physics on edge plasma. It includes the pedestal recovery after the ELM crash, the effect of neutrals on zonal flows regulating anomalous edge plasma transport, novel scrape-off layer plasma instability caused by plasma recycling [2-5].

            Here we review recent results on dynamic plasma-material interactions, discuss some important issues, and outline possible future developments in coupled plasma-wall physics.

 

[1] S. Krasheninnikov, A. Smolyakov, and A. Kukushkin, “On the Edge of Magnetic Fusion Devices”, (Springer Series in Plasma Science and Technology)  (Springer International Publishing Switzerland, Heidelberg, 2020).

[2] S. I. Krasheninnikov, et al. PPCF 57 (2015) 044009.

[3] Y. Zhang, S. I. Krasheninnikov, PPCF 62 (2020) 115018.

[4] Y. Zhang, S. I. Krasheninnikov, R. Masline, R. D. Smirnov, Nucl. Fusion 60 (2020) 106023

[5] S. I. Krasheninnikov, Plasma Physics Reports 47 (2021) 407-409.