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Abstract. The JET experimental campaign has focused on studies in support
of the ITER physics basis. An overview of the results obtained is given
both for the reference ITER scenario, the ELMy H-mode, and for advanced
scenarios which in JET are based on Internal Transport Barriers. JET
studies for the ELMy H-mode have been instrumental for the definition of
ITER-FEAT. Positive elongation and current scaling in the ITER scaling law
have been confirmed, but the observed density scaling fits better a two term
(core and edge) model. Significant progress in neo-classical tearing mode
limits has been made showing that ITER operation seems to be optimised.
Effective helium pumping and divertor enrichment is found to be well within
ITER requirements. Target asymmetries and H-isotope retention are well
simulated by modelling codes taking into account drift flows in the
scrape-off plasmas. Striking improvements in fuelling effectiveness have
been found with the new high field pellet launch facility. Good progress has
been made on scenarios for achieving good confinement at high densities,
both with RI modes and with high field side pellets. Significant development
of advanced scenarios in view of their application to ITER has been
achieved. Integrated advanced scenarios are in good progress with edge
pressure control (impurity radiation). An access domain has been explored
showing in particular that the power threshold increases with magnetic field
but can be significantly reduced when Lower Hybrid current drive is used to
produce target plasma with negative shear. The role of ion pressure peaking
on MHD has been well documented. Lack of sufficient additional heating power
and interaction with the septum at high beta prevents assessment of beta
limits (steady plasmas achieved with
up to 2.6). Plasmas with
non-inductive current (
INI/Ip = 60%), well aligned with plasma
current, high beta and good confinement have also been obtained.
IAEA 2001
