Publications de Theodoros Panis

Sparse representation of signals: from astrophysics to real-time data analysis for fusion plasmas and system optimization analysis for ITER and TCV

Patrick Blanchard, Ambrogio Fasoli, Jonathan Bryan Lister, Duccio Testa, Theodoros Panis, Mattia Albergante

Efficient, real-time and automated data analysis is one of the key elements for achieving scientific success in complex engineering and physical systems, of which two examples are the JET and ITER tokamaks. One problem which is common to these fields is th ...

2016

Measurement of the Radial Profile of the Plasma Isotopic Composition in JET Plasmas Using Alfven Eigenmodes

Patrick Blanchard, Duccio Testa, Theodoros Panis

The measurement of the plasma isotopic composition is necessary in future burning plasma devices such as ITER and DEMO as a tool for optimizing the DT fusion performance. This paper reports on the results of experiments performed on the JET tokamak where T ...

IOP Publishing Ltd2015

Plasma Isotopic Effect on the Damping Rate of Toroidal Alfven Eigenmodes with Intermediate Toroidal Mode Numbers

Patrick Blanchard, Ambrogio Fasoli, Duccio Testa, Theodoros Panis

This paper reports on the results of recent experiments performed on the JET tokamak on toroidal Alfvén eigenmodes (TAEs) with toroidal mode number (n) in the range up to |n|=7. The stability properties of these medium-nTAEs are investigated experimentally ...

2012

Analysis of damping rate measurements of toroidal Alfven eigenmodes as a function of n: part I

Ambrogio Fasoli, Duccio Testa, Theodoros Panis

Complementing the database approach that has been presented in part I, this paper probes into individual plasma discharges and investigates the damping rate variations that are driven by the evolving plasma configurations. In addition to confirming the sta ...

IOP Publishing Ltd2012

Analysis of damping rate measurements of toroidal Alfven eigenmodes as a function of n: part II (vol 52, 023014, 2012)

Ambrogio Fasoli, Duccio Testa, Theodoros Panis

IOP Publishing Ltd2012

Recent JET Experiments on Alfvén Eigenmodes with Intermediate Toroidal Mode Numbers: Measurements and Modelling with the TAEFL code

Patrick Blanchard, Ambrogio Fasoli, Duccio Testa, Theodoros Panis

This paper reports the results of recent experiments performed on the JET tokamak on Alfven eigenmodes (AEs) with toroidal mode number (n) in the range n=3—15. The stability properties of these medium-n AEs are investigated experimentally using a new set o ...

IOP Publishing Ltd2011

The JET Alfven Eigenmode Local Manager for the real-time detection and tracking of a frequency-degenerate spectrum of MHD instabilities

Patrick Blanchard, Ambrogio Fasoli, Pierre Lavanchy, Duccio Testa, Theodoros Panis

We present the real-time VME system used to detect and track MHD instabilities, and particularly Alfven Eigenmodes, on the JET tokamak [J.Wesson, Tokamaks, 3rd ed., Oxford Science Publication, Oxford, 2003, p.617]. This system runs on a 1 kHz clock cycle, ...

Elsevier2011

Direct Measurements of the Damping of Alfvén Eigenmodes for an Assessment of their Stability Limits in Tokamak Plasmas

Theodoros Panis

Direct damping rate measurements of AEs are obtained using the active MHD spectroscopy system installed on the JET tokamak. The system was recently equipped with new antennas, designed to study especially the modes of intermediate toroidal mode number n, | ...

EPFL2010

Optimization of the active MHD spectroscopy system on JET for the excitation of individual intermediate and high-n Alfven eigenmodes

Patrick Blanchard, Ambrogio Fasoli, Duccio Testa, Theodoros Panis

The stability of Alfven eigenmodes (AEs) is studied experimentally in the JET tokamak by observing the plasma response to antenna-driven frequency-sweeping perturbations at the plasma edge. During the 2008/9 experimental campaigns, the complete set of the ...

International Atomic Energy Agency2010

Active excitation and damping rate measurement of intermediate-n Toroidal Alfvén Eigenmodes in JET, C-Mod and MAST plasmas

Ambrogio Fasoli, Duccio Testa, Theodoros Panis

The stability properties of Alfvén Eigenmodes (AEs) are investigated directly using external antenna excitation and detection of stable modes in a variety of plasma configurations in different devices. Dedicated methods to measure the AE damping rate separ ...

2010

AN ALGORITHM FOR THE REAL-TIME, BLIND DETECTION, DECOMPOSITION AND TRACKING OF THE INDIVIDUAL COMPONENTS IN A DEGENERATE, MULTI-HARMONICS SPECTRUM

Patrick Blanchard, Ambrogio Fasoli, Duccio Testa, Theodoros Panis

In this work we report the successful application of an innovative method, based on the Sparse Representation of signals, to perform a real-time, unsupervised detection of the individual components in a frequency degenerate, multi-harmonic spectrum, using ...

IOP Publishing - EPL Association2010

The Dependence of the Damping Rate of Medium-n Toroidal Alfvén Eigenmodes on the Edge Plasma Elongation in JET

Patrick Blanchard, Ambrogio Fasoli, Nicolas Mellet, Duccio Testa, Theodoros Panis

This paper reports the first quantitative analysis of the measurements of the damping rate (gamma/omega) for stable Alfvén Eigenmodes (AEs) with toroidal mode number (n) in the range |n|=3-15 as function of the edge plasma elongation (kappa95). We find tha ...

IOP Publishing Ltd2010