학술논문
On the link between the q-profile and internal transport barriers
Document Type
Article
Author
Source
Plasma Physics and Controlled Fusion; August 2004, Vol. 46 Issue: 8 p1181-1196, 16p
Subject
Language
ISSN
07413335
Abstract
Numerous experiments were performed on JET to clarify the link between rational q, magnetic shear and internal transport barriers (ITBs) by varying the q-profile from a monotonic one to one with a central reversed shear (Challis et al 2002 Plasma Phys. Control. Fusion 44 1031). The q-profile was found to be crucial in two cases: for ITB formation in the presence of a strong negative magnetic shear and for ITBs in the vicinity of low order rational q surfaces with a small magnetic shear. The ITBs of these two types have been modelled and analysed in this work using transport codes (TRANSP, JETTO, TRB). Transport coefficients were calculated using several widely used theories of micro-turbulence and compared with data deduced from the experiment to verify the applicability of the theories. Different underlying physical mechanisms were found to be responsible for ITB formation in a negative magnetic shear and in the vicinity of a rational minimum q.