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Return To: Session OV1 - Overviews 1 (Monday, 19 October)
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The JET Team 1 (Presented by M. L. Watkins )
1 See Appendix of the paper
JET Joint Undertaking, Abingdon, Oxfordshire, United Kingdom
Abstract
JET has recently operated with deuterium-tritium (D-T) mixtures,
carried out an ITER physics campaign in hydrogen, deuterium, D-T and tritium,
installed the Mark IIGB ``Gas Box'' divertor fully by remote handling and
started physics experiments with this more closed divertor. The D-T
experiments set records for fusion power (16.1 MW), ratio of fusion power to
plasma input power (0.62, and 
if a similar plasma could be
obtained in steady-state) and fusion duration (4 MW for 4 s). A large scale
tritium supply and processing plant, the first of its kind, allowed the
repeated use of the 20 g tritium on site to supply 99.3 g of tritium to the
machine. The H-mode threshold power is significantly lower in D-T, but the
global energy confinement time is practically unchanged (no isotope
effect). Dimensionless scaling ``Wind Tunnel'' experiments in D-T extrapolate
to ignition with ITER parameters. The scaling is close to gyroBohm, but the
mass dependence is not correct. Separating the thermal plasma energy into core
and pedestal contributions could resolve this discrepancy (leading to proper
gyroBohm scaling for the core) and also account for confinement degradation at
high density and at high radiated power. Four radio frequency heating schemes
have been tested successfully in D-T, showing good agreement with
calculations. Alpha particle heating has been clearly observed and is
consistent with classical expectations. Internal transport barriers have been
established in optimised magnetic shear discharges for the first time in D-T
and steady-state conditions have been approached with simultaneous internal
and edge transport barriers . First results with the newly installed Mark IIGB
divertor show that the in/out symmetry of the divertor plasma can be modified
using differential gas fuelling, that optimised shear discharges can be
produced, and that krypton gas puffing is effective in restoring L-mode edge
conditions and establishing an internal transport barrier in such discharges.
IAEA 1999