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

Journal Article · Fri Jan 15 04:00:00 EST 2016 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4940330· OSTI ID:22493821

Militello, F.; Omotani, J.; Walkden, N. R. ^[1]; Dudson, B. ^[2]

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1. CCFE, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)
2. Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom)

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.

• OSTI ID: 22493821
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 1 Vol. 23; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

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