Transport in JET deuterium plasmas with optimised shear
Plasmas with the highest deuterium fusion neutron rates yet achieved in JET have been produced by combining a hollow or flat central current profile with a high confinement (H-mode) edge. In these discharges, lower hybrid current drive (LHCD) and interrupted current rise heating (ICRH) preheating, applied early in the current ramp-up phase, freezes in a hollow or flat current density profile. When the combined neutron beam injection (NBI) and ICRH heating power is increased, a region of reduced transport and highly peaked profiles forms during the L-mode phase which persists into the later H-mode phase when the fusion reactivity reaches a maximum. Transport analysis shows the formation of a central region of good confinement (the internal transport barrier (ITB)) which expands with radial velocity. The clearest signatures of this region are large gradients in the ion temperature and toroidal rotation profiles.
Bibliographic Reference: Report: JET-P(97)53 EN (1997) 15pp.
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (GB)
Record Number: 199810432 / Last updated on: 1998-03-31
Original language: en
Available languages: en