PPPL-5387
HSX as an example of a resilient non-resonant divertor
Author: S.A. Lazerson
Abstract: This paper describes an initial description of the
resilient divertor properties ofquasi-symmetric (QS) stellarators
using the HSX (Helically Symmetric eXperiment) configuration as a
test-case. Divertors in high-performance QS stellarators will need
to be resilient to changes in plasma configuration that arise due to
evolution of plasma pressure profiles and bootstrap currents for
divertor design. Resiliency is tested by examining the changes in
strike point patterns from field line following that arise due to
configurational changes. Low strike point variation with high
configuration changes corresponds to high resiliency. The HSX edge
displays resilient properties with configuration changes arising
from 1) wall position, 2) plasma current and 3) external coils. The
resilient behavior is lost if large edge islands intersect the wall
structure. The resilient edge properties are corroborated by heat
flux calculations from the fully 3-D plasma simulations using
EMC3-EIRENE. Additionally, the strike point patterns are found to
correspond to high curvature regions of the magnetic flux surfaces.
Submitted to: Physics of Plasmas
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Download PPPL-53875 MB (30 pp)
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