Abstract
The TCV tokamak is augmenting its unique historical
capabilities (strong shaping, strong electron heating)
with ion heating, additional electron heating compatible
with high densities, and variable divertor geometry, in a
multifaceted upgrade program designed to broaden its
operational range without sacrificing its fundamental
flexibility. The TCV program is rooted in a three-pronged
approach aimed at ITER support, explorations towards
DEMO, and fundamental research. A 1 MW, tangential
neutral beam injector (NBI) was recently installed and
promptly extended the TCV parameter range, with record
ion temperatures and toroidal rotation velocities and
measurable neutral-beam current drive. ITER-relevant
scenario development has received particular attention,
with strategies aimed at maximizing performance through
optimized discharge trajectories to avoid MHD
instabilities, such as peeling-ballooning and
neoclassical tearing modes. Experiments on exhaust
physics have focused particularly on detachment, a
necessary step to a DEMO reactor, in a comprehensive set
of conventional and advanced divertor concepts. The
specific theoretical prediction of an enhanced radiation
region between the two X-points in the low-field-side
snowflake-minus configuration was experimentally
confirmed. Fundamental investigations of the power decay
length in the scrape-off layer (SOL) are progressing
rapidly, again in widely varying configurations and in
both D and He plasmas; in particular, the double decay
length in L-mode limited plasmas was found to be replaced
by a single length at high SOL resistivity. Experiments
on disruption mitigation by massive gas injection and
electron-cyclotron resonance heating (ECRH) have begun in
earnest, in parallel with studies of runaway electron
generation and control, in both stable and disruptive
conditions; a quiescent runaway beam carrying the entire
electrical current appears to develop in some cases.
Developments in plasma control have benefited from
progress in individual controller design and have evolved
steadily towards controller integration, mostly within an
environment supervised by a tokamak profile control
simulator. TCV has demonstrated effective wall
conditioning with ECRH in He in support of the
preparations for JT-60SA operation.
Original language | English |
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Article number | 102011 |
Journal | Nuclear Fusion |
Volume | 57 |
Issue number | 10 |
DOIs | |
Publication status | Published - 23 Jun 2017 |
MoE publication type | A1 Journal article-refereed |
Funding
This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom Research and Training Programme 2014–2018 under grant agreement number 633053. This work was supported in part by the Swiss National Science Foundation.
Keywords
- overview
- TCV
- tokamak