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Abstract. Recent JET results show progress in two directions:
consolidation of the ITER reference scenario, the ELMy H-mode, and
development of regimes with internal transport barriers (ITBs). The
beneficial effect of high triangularity in ELMy H-mode - one of the
features of the new ITER design, has been confirmed in particular to extend
the operation limits. Indeed three different ELMy H-mode scenarios are shown
to allow operation at or above the Greenwald density limit with limited or
no confinement degradation: (1) operation at high triangularity (up to
= 0.47) with controlled gas puffing; (2) operation well above the L-H
transition threshold (
Pin > 2.5PL - H) with controlled gas
puffing; (3) impurity seeding. The level of confidence in the ITER ELMy
H-mode reference scenario has therefore increased further and is high;
research should now focus towards milder ELMs. A very significant progress
in LHCD coupling has been achieved, with routine power in the 2-4 MW range.
LHCD preheat allows to control efficiently the q profile, giving access to
strongly reversed shear plasmas, with very broad ITBs on
Ti,
Te and
ne, achieved at reduced power thresholds.
ITBs are being developed, either towards high performance
(
H
7.5 achieved) or towards steady state
(full non-inductive current drive achieved during 1 second).
IAEA 2001