Transport in the tokamak - reactor edge plasma with strong collisionality. (October 2022)

• Record Type: Journal Article
• Authors: Rozhansky, V.; Kaveeva, E.; Baranovsky, I.; Pitts, R.A.
• Is Part Of: Nuclear materials and energy. Volume 33(2022)
• Publication Date: 2022-10
• Subjects: Nuclear energy -- Periodicals; Nuclear fuels -- Periodicals; Nuclear reactors -- Materials -- Periodicals; Radioactive substances -- Periodicals; 621.4833
• DOI: 10.1016/j.nme.2022.101316
• Languages: English
• ISSNs: 2352-1791

Abstract

Highlights: Strongly collisional plasma transport is significantly affected by motion of neutral particles. Neutrals are dragged along the magnetic field and diffuse in the perpendicular direction. The motion of neutral particles and ions can be largely controlled by the viscosity of atoms. Frequent ion-ion collisions cause of the viscous layer in front of the magnetic presheath. Abstract: In detached divertor regimes, especially in future tokamak-reactors, plasma in the divertor is strongly collisional. When ion-ion and ion-neutral collision frequencies become comparable with the ion gyrofrequency, plasma transport is strongly affected by the motion of neutral particles. This paper demonstrates that in such partially ionized plasma, ion transport is regulated by the motion of neutrals which are dragged along the magnetic field and diffuse in the perpendicular direction due to the ion-neutral friction force. The motion of neutral particles and (due to the friction force) ions is to a large extent controlled by the viscosity of atoms in the presence of charge-exchange collisions. Analytic models are compared with the results of ITER simulations performed with the SOLPS-ITER plasma boundary transport code. Specific attention is paid to currents caused by ion-neutral collisions.