Scrape-off Layer Flows, Magnetic Topology and Influence on the L-H Threshold in a Tokamak

Download or read book Scrape-off Layer Flows, Magnetic Topology and Influence on the L-H Threshold in a Tokamak written by Brian LaBombard and published by . This book was released on 2004 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: The dependence of L-H power threshold on magnetic topology (upper-, lower-null) in a tokamak is linked to near-sonic plasma flows in the high-field side scrape-off layer. Scrape-off layer flow momentum, coupling across the separatrix, imparts a topology-dependent increment to edge and core toroidal rotation (counter-, co-current). In all topologies, rotation increases in the co-current direction with input power: the L-H transition is seen when co-rotation achieves a characteristic level. Correspondingly, higher power is required to attain H-modes in upper- versus lower-null (with BxGradB down).