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Title: Investigation of the effect of resistivity on scrape off layer filaments using three-dimensional simulations

The propagation of filaments in the Scrape Off Layer (SOL) of tokamaks largely determines the plasma profiles in the region. In a conduction limited SOL, parallel temperature gradients are expected, such that the resistance to parallel currents is greater at the target than further upstream. Since the perpendicular motion of an isolated filament is largely determined by balance of currents that flow through it, this may be expected to affect filament transport. 3D simulations have thus been used to study the influence of enhanced parallel resistivity on the dynamics of filaments. Filaments with the smallest perpendicular length scales, which were inertially limited at low resistivity (meaning that polarization rather than parallel currents determines their radial velocities), were unaffected by resistivity. For larger filaments, faster velocities were produced at higher resistivities due to two mechanisms. First parallel currents were reduced and polarization currents were enhanced, meaning that the inertial regime extended to larger filaments, and second, a potential difference formed along the parallel direction so that higher potentials were produced in the region of the filament for the same amount of current to flow into the sheath. These results indicate that broader SOL profiles could be produced at higher resistivities.
Authors:
 [1] ;  [2] ; ; ;  [3] ;  [1]
  1. Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom)
  2. (United Kingdom)
  3. CCFE, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)
Publication Date:
OSTI Identifier:
22493821
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 23; Journal Issue: 1; Other Information: (c) 2016 EURATOM; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CURRENTS; FILAMENTS; PLASMA RADIAL PROFILES; PLASMA SCRAPE-OFF LAYER; POLARIZATION; RADIAL VELOCITY; TEMPERATURE GRADIENTS; THREE-DIMENSIONAL CALCULATIONS; TOKAMAK DEVICES