Prime pagine RA2010FUS:Copia di Layout 1 - ENEA - Fusione

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progress report
2010
mainly related to the experimental data of the most recent campaigns (2008–2009), particularly those of the
high current discharges. During 2010 a new calibration algorithm [1.97] was developed and completely
validated for offline analysis to the purpose of to overcoming this problem.
Plasma control
The plasma pontrol activity was carried out in collaboration with CREATE Consortium. Fusion relevant
theoretical studies, tool development and technology studies were carried out in the framework of the general
support to physics activities and underlying technology. A significant fraction of the activity has been addressed
to the following fields:
Modelling of resistive wall modes. The dispersion relation of resistive wall modes (RWM) has been derived
when a cylindrical plasma circumvented by a thin resistive shell and an outer, non–conducting, ferromagnetic
wall is considered [1.98]. It has been demonstrated that the resulting growth rate is always higher than that in
the absence of any ferromagnetic materials, hence it always provides a destabilizing effect, which is consistent
with previous results similarly obtained for somewhat different arrangements. The growth rate increase does
not depend on the plasma configuration but only on the poloidal mode number as well as on the physical
and geometrical properties of the ferromagnetic shell. Several calculations have been made to verify these
findings on the JET tokamak with the CREATE L code. Although the JET geometry is very different from the
simplified case treated analytically, the main qualitative conclusion is absolutely confirmed.
Development of a real–time framework for data acquisition and control in fusion experiments. The CREATE
group has contributed in the development of the MARTe [1.99]. MARTe is a modular real–time
multiplatform C++ framework tailored at, but not restricted to, the development and deployment of control
systems. This framework has been recently adopted to drive the vertical stabilization of the JET tokamak
[1.100,1.101].
Breakdown analysis. A modeling activity has been carried out by using a refined CREATE L state space model
[1.102] in order to analyze the electromagnetic conditions of JET breakdown, also for what concerns the
possible impact of the new radial field system on plasma breakdown [1.103]. This work identified for the first
time the radial field due to the up-down asymmetric gaps in the iron core and the relative influence on the
field null.
Current limit avoidance. The preliminary activity for the implementation of a current limit avoidance system
within the existing architecture of the shape controller has been carried out [1.104]. In particular, the detailed
design document and the Level–1 interface documents have been issued at the end of the year.
Presentation of the main achievements of the PCU2 projects. In 2009 the PCU2 project was mainly focused
on designing and commissioning the new vertical stabilization system of JET. Therefore, little time was
dedicated to the preparation of the report, the methodic and systematic analysis of the experimental results,
and the presentation of the achievements to the scientific community. This has been effectively done in 2010,
with the compilation of the final report, the presentation of the commissioning phase, and the illustration of
the main achievements [1.105].
References
[1.1] N.J. Fisch, Phys. Rev. Letts 41, 873–876 (1978)
[1.2] S. Bernabei et al., Phys. Rev. Letts 49, 1255–1258 (1982)
[1.3] R. Cesario et al., Phys. Rev. Letts 92, 17, 175002 (2004)
[1.4] R. Cesario et al., Nature Comm. 1(5),55 (2010)
[1.5] R. Cesario et al., Plasma edge density and lower hybrid current drive in JET (Joint European Torus), submitted
to Plasma Phys. Contr. Fusion
[1.6] F. Zonca et al., Nucl Fusion 47, 1588 (2007)
[1.7] C. Nguyen et al., Theoretical and experimental analysis of the destabilization of modes driven by fast particles
in Tore-Supra, Proceedings of the 23rd IAEA Fusion Energy Conference (Daejon 2010), CN–180 – Paper
EXS/P7–02 (2010)