Effect of q-profile modification by LHCD on internal transport barriers in JET*Effect of q-profile modification by LHCD on internal transport barriers Effect of q-profile modification by LHCD on internal transport barriers in JET
Abstract
Optimized shear (OS) experiments in JET can generate an internal transport barrier (ITB) during a high power heating phase early in the plasma discharge. A strong link is generally observed between the formation of the barrier and the location of an integer q magnetic surface within a low magnetic shear (s = r/q(dq/dr)) region of the plasma. However, if the q-profile for such experiments is modified by applying lower hybrid heating and current drive (LHCD) before the main heating pulse, to provide a region of reduced or negative magnetic shear in the plasma core, ITBs can be formed the location of which does not exhibit any apparent association with a particular internal magnetic surface. Initial results suggest that q-profile modification using an LHCD prelude can also be used to reduce the heating power level required for ITB generation.
- Publication:
-
Plasma Physics and Controlled Fusion
- Pub Date:
- July 2001
- DOI:
- 10.1088/0741-3335/43/7/303
- Bibcode:
- 2001PPCF...43..861C