Intrinsic Instabilities in X-Point Geometry: a Tool to Understand and Predict the Scrape Off Layer Transport in Standard and Advanced Divertors

Intrinsic Instabilities in X-Point Geometry: a Tool to Understand and Predict the Scrape Off Layer Transport in Standard and Advanced Divertors

Intrinsic Instabilities in X-Point Geometry: a Tool to Understand and Predict the Scrape Off Layer Transport in Standard and Advanced Divertors 150 150 UKAEA Opendata
CCFE-PR(15)22

Intrinsic Instabilities in X-Point Geometry: a Tool to Understand and Predict the Scrape Off Layer Transport in Standard and Advanced Divertors

Intrinsic Scrape Off Layer (SOL) instabilities are studied using flute approximation and incorporating the appropriate sheath boundary conditions at the target. The linear growth rate and the structure of the modes are obtained. The associated diffusion is estimated using a ?/k2? approach for the fastest growing modes. The model used includes curvature and sheath drives, finite Larmor radius effects and partial line tying at the target. The magnetic geometry is obtained using current carrying wires, representing the plasma current and the divertor coils, and naturally generates X-point geometry and magnetic shear effects. The calculation is performed for ITER relevant parameters and scans in SOL width and distance from the separatrix are presented. In addition to a standard lower single null, Super-X and Snowflake configurations are examined in order to assess the importance of the geometry on the stability of the boundary plasma.

Collection:
Journals
Journal:
Journal of Nuclear Materials
Publisher:
Elsevier
Published date:
08/01/2015