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Stefano Alberti

Cette personne a quitté l’EPFL

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Publications associées (130)

Page 2 sur 7

A Validation Roadmap of Multi-Physics Simulators of the Resonator of MW-Class CW Gyrotrons for Fusion Applications

Stefano Alberti, Francisco Sanchez

For a few years the multi-physics modelling of the resonance cavity (resonator) of MW-class continuous-wave gyrotrons, to be employed for electron cyclotron heating and current drive in magnetic confinement fusion machines, has gained increasing interest. ...

MDPI2021

Start-up scenario studies in gyrotron oscillator using a novel linear and spectral code

Stefano Alberti, Minh Quang Tran, Jean-Philippe Hogge, Jérémy Genoud, Trach-Minh Tran

A linear and spectral model has recently been developed [1], describing the self-consistent wave-particle interaction in a gyrotron oscillator. The spectral approach, compared to commonly used time-evolution approaches, has the possibility to describe all ...

IEEE2016

Current profile tailoring using localized electron cyclotron heating in highly elongated TCV plasmas

Olivier Sauter, Stefano Coda, Timothy Goodman, Stefano Alberti, Antoine Pochelon, Patrick Blanchard, Yann Camenen, Laurie Porte, Andrea Scarabosio, Gilles Arnoux

Radially localized electron cyclotron heating (ECH) at the 2nd harmonic (X2) is used to tailor the current profile through the modification of the temperature, and hence conductivity, profiles. The optimal conditions for current profile broadening are inve ...

IOP Publishing Ltd2007

TCV heating and divertor upgrades

Ambrogio Fasoli, Basil Duval, Stefano Alberti, Jean-Marc Moret, Holger Reimerdes, Christian Gabriel Theiler, Alexander Karpushov, Matthieu Toussaint, Marcelo Baquero Ruiz, Dario Vaccaro

The operational range and the reactor relevance of the TCV experiments are being enhanced by two sets of major upgrades. The first includes the installation of neutral beam injection (NBI) and new electron cyclotron (EC) auxiliary heating sources, to reach ...

IOP Publishing Ltd2020

Operations with Spherical Calorimetric Loads in Different Configurations at Gyrotron Test Stands at EPFL and QST

Timothy Goodman, Stefano Alberti, Jean-Philippe Hogge, Damien Fasel, Miguel Filipe Silva Füglister

A research activity in the Institute for Plasma Science and Technology of National Research Council (ISTP-CNR, Italy, former IFP-CNR) and in L.T. Calcoli (LTC, Italy) is aimed at the design and construction of calorimetric loads for absorption and measurem ...

AMER INST PHYSICS2020

Third-harmonic X-mode, real-time controlled top-launch ECW experiments on TCV tokamak

Richard Pitts, Yves Martin, Stefano Alberti, Laurie Porte, Alexander Karpushov, Alessandro Bortolon, Gilles Arnoux

In the moderate magneticfield of TCV (1.5T), the recently installed X3 system (3 gyrotrons @118 GHz, 0.45 MW/each, 2s) broadens the operational space with the possibility of heating plasmas at high density, well above the cutoff density of the X2 system (X ...

2005

EU DEMO EC system preliminary conceptual design

Minh Quang Tran, Stefano Alberti, Ioannis Pagonakis

The engineering design and R&D of auxiliary heating systems and their sub-systems are a key activities in the frame of the present conceptual design phase for a first of a kind DEMOnstration Fusion Power Plant in order to develop a system capable of achiev ...

ELSEVIER SCIENCE SA2018

Experimental characterization of the TCV dual-frequency gyrotron and validation of numerical codes including the effect of After Cavity Interaction

Timothy Goodman, Stefano Alberti, Jean-Philippe Hogge, Damien Fasel, Jérémy Genoud, Ugo Siravo, Jérémie Dubray, Matthieu Toussaint, Falk Hans Braunmüller, François Jean Gaston Legrand

A dual-frequency gyrotron has been developed within the context of the recent Tokamak à Configuration Variable (TCV) upgrade. The gyrotron is designed to generate a 1 MW, 2 seconds RF wave at 84 or 126 GHz. Before integrating the gyrotrons in the TCV tokam ...

2024

140 GHz high-power gyrotron development for the stellarator W7-X

Stefano Alberti, Jean-Philippe Hogge

Electron cyclotron resonance heating (ECRH) has proven to be one of the most attractive heating schemes for stellarators. Therefore, ECRH was chosen to be the main heating method for the Wendelstein 7-X stellarator (W7-X) now under construction at IPP Grei ...

2005

High-Field C-13 Dynamic Nuclear Polarization in Nanodiamond

Stefano Alberti, Jean-Philippe Ansermet, Serguei Sekatski, Jérémy Genoud, Murari Soundararajan, Dongyoung Yoon

Hyperpolarization in diamond via dynamic nuclear polarization (DNP) has attracted a lot of interest for various applications as diamond exhibits extremely long C-13 spin relaxation times and has endogenous polarizing agents in the form of crystalline defec ...

2019

Cryogenic single-chip electron spin resonance detector

Stefano Alberti, László Forró, Giovanni Boero, Andrzej Sienkiewicz, Jens Anders, Gabriele Gualco

We report on the design and characterization of a single-chip electron spin resonance detector, operating at a frequency of about 20 GHz and in a temperature range extending at least from 300 K down to 4 K. The detector consists of an LC oscillator formed ...

Academic Press Inc - Elsevier Science2014

Homogenous power distribution along gyrotron collector walls

Stefano Alberti, Jean-Philippe Hogge, Damien Fasel, Ugo Siravo, Jérémie Dubray, Pierre-François Isoz, François Jean Gaston Legrand, Miguel Filipe Silva Füglister

EC RF power sources will play a major role in the future operation of large scale tokamaks (ITER, DEMO). A 1MW/170GHz gyrotron is the standard RF power unit considered for ITER. Even though the efficiency of such devices has been significantly increased th ...

2023

Manufacturing and Test of the 1 MW Long-Pulse 84/126 GHz Dual-Frequency Gyrotron for TCV

Stefano Alberti, Jean-Philippe Hogge, Damien Fasel, Ioannis Pagonakis, Blaise Marlétaz, Jérémy Genoud, Jérémie Dubray, François Jean Gaston Legrand

An 1 MW long-pulse (2s), 84/126 GHz dual frequency gyrotron has been produced by THALES MSI, France responding to the needs for upgrading the ECH system of the TCV tokamak The initial tests of the prototype carried out at EPFL, Switzerland, have verified a ...

IEEE2019

Electron cyclotron emission spectrometry on the Tokamak a Configuration Variable

Ambrogio Fasoli, Timothy Goodman, Stefano Alberti, Patrick Blanchard, Laurie Porte, Igor Klimanov

Electron cyclotron emission (ECE) measurements are an important component of the diagnostic suite on the Tokamak a Configuration Variable (TCV) [F. Hoffman , Plasma Phys. Controlled Fusion 36, B277 (1994)]. A recently installed, 24-channel dual-conversion ...

2005

Self-consistent formation and steady-state characterization of trapped high-energy electron clouds in the presence of a neutral gas background

Guillaume Michel Le Bars, Stefano Alberti, Jean-Philippe Hogge, Joaquim Loizu Cisquella, Francesco Romano

This study considers the self-consistent formation and dynamics of electron clouds interacting with a background neutral gas through elastic and inelastic (ionization) collisions in coaxial geometries similar to gyrotron electron guns. These clouds remain ...

American Institute of Physics (AIP)2022

THz-waves channeling in a monolithic saddle-coil for Dynamic Nuclear Polarization enhanced NMR

Stefano Alberti, Jean-Philippe Ansermet, Emile Jacques de Rijk, Alessandro Macor

A saddle coil manufactured by electric discharge machining (EDM) from a solid piece of copper has recently been realized at EPFL for Dynamic Nuclear Polarization enhanced Nuclear Magnetic Resonance experiments (DNP-NMR) at 9.4 T. The corresponding electrom ...

Academic Press Inc - Elsevier Science2011

Tests and Qualification of the European 1 MW, 170 GHz CW Gyrotron in an ITER relevant configuration at SPC

Timothy Goodman, Stefano Alberti, Jean-Philippe Hogge, Francisco Sanchez, Jérémy Genoud

After an initial testing period at the Karlsruhe Institute of Technology, the upgraded EU 1 MW, 170 GHz continuous wave (CW) industrial prototype gyrotron (TH1509U) for Electron Cyclotron Resonance Heating and Current Drive (ECRH&CD) in ITER has been trans ...

IEEE2022

Optically isolated millimeter-wave detector for the Toroidal Plasma Experiment

Anja Skrivervik, Timothy Goodman, Stefano Alberti, Ivo Furno, Gennady Plyushchev, Marcelo Baquero Ruiz, Oulfa Chellaï, Fabian Manke, Paolo Micheletti

We have designed and built an optically isolated millimeter-wave detection system to prevent interference from a nearby, powerful, 2.45 GHz microwave source in millimeter-wave propagation experiments in the TORoroidal Plasma EXperiment (TORPEX). A series o ...

2018

Parasitic Oscillations in Smooth-Wall Circular Symmetric Gyrotron Beam Ducts

Stefano Alberti, Minh Quang Tran, Jean-Philippe Hogge, Trach-Minh Tran, Jérémy Genoud

In order to study parasitic oscillation that may occur in a realistic beam duct upstream to the gyrotron cavity, the self-consistent linear and spectral code TWANGlinspec has been modified. The large inhomogeneities in the smooth-wall beam duct geometry or ...

2018

Millimeter-wave beam scattering and induced broadening by plasma turbulence in the TCV tokamak

Stefano Alberti, Timothy Goodman, Ivo Furno, Paolo Ricci

The scattering of millimeter-wave beams from electron density fluctuations and the associated beam broadening are experimentally demonstrated. Using a dedicated setup, instantaneous deflection and (de-)focusing of the beam due to density blobs on the beam ...

IOP Publishing Ltd2021