Operation at high performance in optimised shear plasmas in JET
This paper explores the improvement of confinement regimes in tokamaks. Heating during the early part of the current rise phase gives a low or negative magnetic shear in the centre of the JET plasmas. Under these conditions the confinement improves with high additional heating power heating during the current ramp-up phase of the discharge. The reduction in the transport manifests itself as a peaking of the profiles with a large gradient region near r/a=0.55. The best discharges have no transport barrier at the edge of the plasma (L-mode). This allows central power deposition by the neutral beams in JET. A control of the plasma pressure, using feedback of the additional heating power in real-time, minimizes the impact of magnetohydrodynamic (MHD) instabilities.
Bibliographic Reference: Report: JET-P(97)29 EN (1997) 12pp.
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (GB)
Record Number: 199711637 / Last updated on: 1997-12-09
Original language: en
Available languages: en