Publications by Stefano Coda | EPFL Graph Search

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The TCV tokamak contributes to physics understanding in fusion reactor research by a wide set of experimental tools, like flexible shaping and high power ECRH. A 1MW, 25 keV deuterium heating neutral beam (NB) has been installed in 2015 and it was operated ...

Following recent observations of unstable Toroidal Alfven Eigenmodes (TAEs) in a counter-current Neutral Beam Injection (NBI) scenario developed in TCV, an in-depth analysis of the impact of such modes on the global confinement and performance is carried o ...

In this contribution we present OES measurements in the JET tokamak of the deuterated NH (ND) radical and the correlation between results of those experiments and measurement of ammonia production. The observation region covers most of the divertor and its ...

An accurate calibration of the JET neutron diagnostics with a 14 MeV neutron generator was performed in the first half of 2017 in order to provide a reliable measurement of the fusion power during the next JET deuterium-tritium (DT) campaign. In order to m ...

Selected set of samples from JET ITER-Like Wall (JET-ILW) divertor tiles exposed in 2015-2016 has been analysed using Thermal Desorption Spectrometry (TDS). The deuterium (D) amounts obtained with TDS were compared with Nuclear Reaction Analysis (NRA). The ...

Experiments, gyrokinetic simulations and transport predictions were performed to investigate if a negative triangularity (NT) L-mode option for the Divertor Tokamak Test (DTT) full-power scenario would perform similarly to the positive triangularity (PT) H ...

The Advanced Tokamak scenario, one of the modes of operation being considered for ITER, relies on the attainment of a high bootstrap current fraction. This scenario is typically characterized by an internal transport barrier (ITB). An internal feedback loop then governs the current profile, which strongly affects the confinement and thus the properties and location of the high-gradient region, where in turn the bootstrap current component is localized. The bootstrap current fraction can reach 100% only if t

Electron cyclotron resonance heating (ECRH) of high-density tokamak plasmas is limited because of reflections of the waves at so-called wave cutoffs. Electron Bernstein wave (EBW) heating (EBWH) via a double mode conversion process from ordinary (O)-mode, ...

Beryllium limiter marker tiles were exposed to plasma in the Joint European Torus to diagnose the erosion of main chamber wall materials. A limiter marker tile consists of a beryllium coating layer (7-9 mu m) on the top of bulk beryllium, with a nickel int ...

Plasma shape control is a fundamental tool for effective tokamak operation, allowing improved plasma performance and the pursuit of challenging scientific objectives. In this framework, the Tokamak á Configuration Variable (TCV) of the École Polytechnique ...

The Alfvén instability nonlinearly excited the energetic-particle-driven geodesic acoustic mode on the ASDEX-Upgrade tokamak, as demonstrated experimentally. The mechanism of the energetic-particle-driven geodesic acoustic mode excitation and the mode nonl ...

The role played by electron density fluctuations near the plasma edge on rf current drive in tokamaks is assessed quantitatively. For this purpose, a general framework for incorporating density fluctuations in existing modelling tools has been developed. I ...

Tokamaks are experimental nuclear fusion reactors that exploit magnetic-field-generating coils to confine a plasma. In these devices, plasma shape control is crucial to achieving high performance and pursuing challenging scientific objectives. With its lar ...

The high confinement regime (H-mode) is considered fundamental for high-performance operation in next-step tokamaks. It is generally characterized by the occurrence of edge localized modes (ELMs), even though several no-ELM and small-ELM regimes have extended their operational space in the past years (Viezzer et al 2023 Nucl. Mater. Energy 34 101308). The control and suppression of these modes is a priority for the development of scenarios with a confinements good enough for the ITER baseline (Sips et al 20

Combined high-fusion performance and long-pulse operation is one of the key integration challenges for fusion energy development in magnetic devices. Addressing these challenges requires an integrated vision of physics and engineering aspects with the purp ...

A control-oriented approach to the monitoring of wall power flux densities on ITER has been successfully developed. It is based on real-time equilibrium reconstruction in 2-D which is then used to describe the deposited heat flux as a poloidal flux functio ...

Neutron emission spectroscopy is a diagnostic technique that allows for energy measurements of neutrons born in nuclear reactions. The JET tokamak fusion experiment (Culham, UK) has a special role in this respect as advanced spectrometers for 2.5 MeV and 1 ...

Bayesian integrated data analysis combines measurements from different diagnostics to jointly measure plasma parameters of interest such as temperatures, densities, and drift velocities. Integrated data analysis of fast-ion measurements has long been hampe ...

In this work, we study the interplay between triangularity and micro-tearing turbulence using linear and nonlinear flux tube GENE simulations. We consider scenarios with negative and positive triangularity plasma shaping taken from existing tokamaks (TCV, DIII-D, MAST-U and SMART) and EU-DEMO. The study of all these tokamaks reveals a coherent picture. Negative triangularity geometry is more susceptible to micro-tearing modes (MTM), which, when present, make transport much worse than in positive triangulari

This work refers to the development, commissioning, and testing of a control algorithm to optimize the electron cyclotron resonance heating (ECRH) power injection in the Tokamak á configuration variable (TCV). The aim is to understand how the injected microwave polarization, set by corrugated mirrors in the waveguide, influences relevant plasma parameters, namely, electron temperature and stray radiation. To accomplish this task, real-time polarization control is required; therefore, a proportional-integral

Stefano Coda

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Status, scientific results and technical improvements of the NBH on TCV tokamak

Study of fast-ion-driven toroidal Alfvén eigenmodes impacting on the global confinement in TCV L-mode plasmas

Molecular ND Band Spectroscopy in the Divertor Region of Nitrogen Seeded JET Discharges

Neutron spectroscopy measurements of 14 MeV neutrons at unprecedented energy resolution and implications for deuterium-tritium fusion plasma diagnostics

Investigation of deuterium trapping and release in the JET divertor during the third ILW campaign using TDS

Negative triangularity scenarios: from TCV and AUG experiments to DTT predictions

Full Bootstrap Discharge Sustainment in Steady State in the TCV Tokamak

Electron Bernstein Wave Heating and Emission in the TCV Tokamak

Micro ion beam analysis for the erosion of beryllium marker tiles in a tokamak limiter

Design and implementation of a model-based hierarchical architecture for plasma shape control in the TCV tokamak

Nonlinear excitation of energetic particle driven geodesic acoustic mode by resonance overlap with Alfvén instability in ASDEX Upgrade

RF current drive and plasma fluctuations

Design of a novel plasma shape controller for the TCV tokamak

Experimental characterization of inter-ELM modes in type-I ELMy scenarios at TCV using the thermal helium beam diagnostic

Long plasma duration operation analyses with an international multi-machine (tokamaks and stellarators) database

Experimental implementation of a real-time power flux estimator for the ITER first wall on the TCV tokamak

Neutron emission spectroscopy of D plasmas at JET with a compact liquid scintillating neutron spectrometer

Bayesian Integrated Data Analysis of Fast-Ion Measurements by Velocity-Space Tomography

On the interplay between plasma triangularity and micro-tearing turbulence

Design and Commissioning of Control Algorithms for Optimal ECRH Power Injection in TCV’s Plasma