3-D simulations of plasma transport in the ring limiter scrape-off layer of tokamak Aditya

Abstract

Aditya tokamak has a circular poloidal ring limiter at one toroidal location and therefore its contact with plasma produces a complex 3D flow pattern in the SOL plasma region [1]. Presently plasma flow in the SOL region is being measured using Mach probes at a few discrete locations and can be properly understood only with the help of a full 3D simulation taking the toroidal asymmetry introduced by the ring limiter into account. We have therefore carried out plasma transport studies for the Aditya configuration using the 3D Monte-Carlo plasma–neutral code EMC3-Eirene [1,2]. The toroidal asymmetry of the plasma parameters and flows indicate the importance of limiter as a localized sink of plasma. The plasma and neutral particle density show a corresponding variation in the toroidal direction as well as in its radial penetration depth. The plasma configurations are characterized by sharp gradients in the edge and show the presence of extended zones of large parallel flow shear in the SOL and edge regions. The plasma flow patterns show poloidal modulations which correspond to effects of a rational surface interacting with the limiter.