Flow structure and shear generation in the 3D SOL of a circular tokamak plasma in Aditya

Abstract

The presence of a poloidal ring limiter in the tokamak Aditya, which has a circular plasma, presents an interesting scrape-off layer (SOL) plasma configuration where small to large scale spatial variations of plasma parameters are expected. Flow shears in the Aditya SOL are routinely observed and their strong correlations with experimentally measured edge fluctuations in the floating potential and SOL currents/drifts have been thoroughly investigated in the recent past. The first implementation of the three-dimensional (3D) SOL plasma transport simulation code EMC3-EIRENE allows the possibility of investigating the SOL's complexity and associated short and long scale spatial patterns in the flow and plasma transport, and their impact on the confinement properties of the plasma in the edge region. A detailed investigation of the first results from the 3D plasma transport simulations shows interesting 3D flow patterns and the existence of resulting parallel and radial flow shears in the device's SOL. In this work the origin of these complex flow patterns is studied and their correlation with the observed behavior of the flows in the device is discussed.