Two-dimensional analysis of limiter/divertor transition in scrape-off layer plasmas

Abstract

The structures of scrape-off layer and divertor plasmas have been studied numerically with a neutral code and a two-dimensional fluid code. Doublet-III is taken as an example for an open divertor configuration. A decisive parameter is the distance between the plasma surface (determined by the magnetic separatrix) and the limiter, which is varied in order to assess the interaction of the plasma with the limiter as well as the effect of neutrals on the main plasma. The minimum value of the limiter clearance needed to prevent plasma-limiter interaction is determined. The scaling of the edge temperature and the dependence of the e-folding length of the scrape-off layer plasma on the heating power are obtained.

Model of the H-mode in tokamaks

“…As discussed in Refs [52,53], the edge temperature increases when the connection length becomes longer, and geometrical parameters such as the aspect ratio also have an influence on the edge temperature. Here, we include only the dependence on the size a and disregard the dependences on R/a or cos 0 m , or on the distance between the limiter/x-point and the wall, etc.…”

“…The transition from the edge temperature to the SOL temperature must be continuous at the midplane of the torus. Twodimensional analyses have been performed analytically and numerically [52,53]. Assuming that the perpendicular diffusivity has a Bohm-like dependence 1 and that the parallel diffusion is given by the classical value of the collisional plasma in the SOL, the edge temperature scaling is obtained as…”

A review of radiative detachment studies in tokamak advanced magnetic divertor configurations

“…However, neither of the experiments specifically focused on the advanced magnetic configuration effects. In parallel, divertor model development and one-and two-dimensional fluid modeling of these experiments enabled understanding of the divertor low-recycling, high-recycling and highly radiative regimes, including numerical demonstration of properties like parallel electron pressure drop, momentum loss, recycling and radiative cooling [118][119][120].…”

Modeling of supersonic plasma flow in the scrape-off layer

“…The favorable detached operation regime exists only in the presence of strong pressure gradients along the magnetic field in the SOL and leads to increased emission of neutral particles from the divertor volume [2]. Therefore, the predictive modeling of the edge plasma, which has experienced very significant progress 0021-9991/$ -see front matter Ó 2007 Elsevier Inc. All during past years from two-point models [3,4] and the onion-skin method [5] to two-and three-dimensional simulations [6][7][8][9], remains an extremely important issue in fusion research.…”