R. Coelho

The European Integrated Tokamak Modelling (ITM) effort: achievements and first physics results

A selection of achievements and first physics results are presented of the European Integrated Tokamak Modelling Task Force (EFDA ITM-TF) simulation framework, which aims to provide a standardized platform and an integrated modelling suite of validated numerical codes for the simulation and prediction of a complete plasma discharge of an arbitrary tokamak. The framework developed by the ITM-TF, based on a generic data structure including both simulated and experimental data, allows for the development of sophisticated integrated simulations (workflows) for physics application.The equilibrium reconstruction and linear magnetohydrodynamic (MHD) stability simulation chain was applied, in particular, to the analysis of the edgeMHDstability of ASDEX Upgrade type-I ELMy H-mode discharges and ITER hybrid scenario, demonstrating the stabilizing effect of an increased Shafranov shift on edge modes. Interpretive simulations of a JET hybrid discharge were performed with two electromagnetic turbulence codes within ITM infrastructure showing the signature of trapped-electron assisted ITG turbulence. A successful benchmark among five EC beam/ray-tracing codes was performed in the ITM framework for an ITER inductive scenario for different launching conditions from the equatorial and upper launcher, showing good agreement of the computed absorbed power and driven current. Selected achievements and scientific workflow applications targeting key modelling topics and physics problems are also presented, showing the current status of the ITM-TF modelling suite.

Synthetic Diagnostics In The European Union Integrated Tokamak Modelling Simulation Platform

Abstract The European Union Integrated Tokamak Modelling Task Force (ITM-TF) has developed a standardized platform and an integrated modeling suite of codes for the simulation and prediction of a complete plasma discharge in any tokamak. The framework developed by ITM-TF allows for the development of sophisticated integrated simulations (workflows) for physics application, e.g., free-boundary equilibrium with feedback control, magnetohydrodynamic stability analysis, core/edge plasma transport, and heating and current drive. A significant effort is also under way to integrate synthetic diagnostic modules in the ITM-TF environment, namely, focusing on three-dimensional reflectometry, motional Stark effect, and neutron and neutral particle analyzer diagnostics. This paper gives an overview of the conceptual design of ITM-TF and preliminary results of the aforementioned synthetic diagnostic modules.

Corrigendum: The European Integrated Tokamak Modelling (ITM) effort: achievements and first physics results (2014 Nucl. Fusion 54 043018)

Reference EPFL-ARTICLE-202347doi:10.1088/0029-5515/54/9/099501View record in Web of Science Record created on 2014-10-23, modified on 2017-05-12

A real-time algorithm for the harmonic estimation and frequency tracking of dominant components in fusion plasma magnetic diagnostics

The real-time tracking of instantaneous quantities such as frequency, amplitude, and phase of components immerse in noisy signals has been a common problem in many scientific and engineering fields such as power systems and delivery, telecommunications, and acoustics for the past decades. In magnetically confined fusion research, extracting this sort of information from magnetic signals can be of valuable assistance in, for instance, feedback control of detrimental magnetohydrodynamic modes and disruption avoidance mechanisms by monitoring instability growth or anticipating mode-locking events. This work is focused on nonlinear Kalman filter based methods for tackling this problem. Similar methods have already proven their merits and have been successfully employed in this scientific domain in applications such as amplitude demodulation for the motional Stark effect diagnostic. In the course of this work, three approaches are described, compared, and discussed using magnetic signals from the Joint European Torus tokamak plasma discharges for benchmarking purposes.

Axisymmetric oscillations at L-H transitions in JET: M-mode

L to H transition studies at JET have revealed an n = 0, m = 1 magnetic oscillation starting immediately at the L to H transition (called M-mode for brevity). While the magnetic oscillation is pres ...

MHD marking using the MSE polarimeter optics in ILW JET plasmas

In this communication we propose a novel diagnostic technique, which uses the collection optics of the JET Motional Stark Effect (MSE) diagnostic, to perform polarimetry marking of observed MHD in high temperature plasma regimes. To introduce the technique, first we will present measurements of the coherence between MSE polarimeter, electron cyclotron emission, and Mirnov coil signals aiming to show the feasibility of the method. The next step consists of measuring the amplitude fluctuation of the raw MSE polarimeter signals, for each MSE channel, following carefully the MHD frequency on Mirnov coil data spectrograms. A variety of experimental examples in JET ITER-Like Wall (ILW) plasmas are presented, providing an adequate picture and interpretation for the MSE optics polarimeter technique.

Erratum: The European Integrated Tokamak Modelling (ITM) effort: Achievements and first physics results (Nuclear Fusion (2014) 54 (043018))

Reference EPFL-ARTICLE-202347doi:10.1088/0029-5515/54/9/099501View record in Web of Science Record created on 2014-10-23, modified on 2017-05-12

EFD-C(13)03/32 ITER Like Wall Impact on MHD Instabilities in JET Discharges

1Consorzio RFX, EURATOM-ENEA Association, Corso Stati Uniti 4, 35127 Padova, Italy 2Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, OX14 3DB, UK 3Associazione EURATOM-ENEA sulla Fusione, C.R. Frascati, Roma, Italy 4Association EURATOM-CEA, CEA/DSM/IRFM, Cadarache 13108 Saint Paul Lez Durance, France 5Associacao EURATOM/IST, Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, Av Rovisco Pais, 1049-001 Lisbon, Portugal 6FOM institute DIFFER, EURATOM association, P.O. Box 1207, Nieuwegein, Netherlands 7Max-Planck-Institut fur Plasmaphysik, EURATOM-Assoziation, D-85748 Garching, Germany 8Associazione EURATOM-ENEA sulla Fusione, Universita di Roma, Italy