Publications by Stefano Alberti

Electron trapping in gyrotron electron guns: Validation of the FENNECS code with the T-REX experiment

Stefano Alberti, Timothy Goodman, Jean-Philippe Hogge, Mario Ludovico Podesta, Joaquim Loizu Cisquella, Jérémy Genoud, Guillaume Michel Le Bars, Falk Hans Braunmüller, Francesco Romano

Gyrotrons are essential devices for the development of nuclear fusion, but their design and reliable operation still present numerous challenges. In particular, certain gyrotrons encounter issues related to trapped electron clouds in the magnetron injectio ...

AIP Publishing2025

Design and First Tests of the Trapped Electrons Experiment T-REX

Stefano Alberti, Damien Fasel, Joaquim Loizu Cisquella, Severino Antonioni, Jérémy Genoud, Steve Couturier, Francesco Romano

Gyrotrons are essential for electron cyclotron resonance heating (ECRH) in fusion reactors, making efficient operation crucial for advancing fusion energy. Past experiments revealed instability issues due to trapped electrons in the magnetron injection gun ...

AIP Publishing2024

Experimental research on the TCV tokamak

Patrick Blanchard, Stefano Alberti, Ambrogio Fasoli, Timothy Goodman, Yves Martin, Olivier Sauter, Henri Weisen, Ivo Furno, Holger Reimerdes, Jean-Philippe Hogge, Stefano Coda, Alexander Karpushov, Yanis Andrebe, Duccio Testa, Benoît Labit, Christian Gabriel Theiler, Federico Alberto Alfredo Felici, Jérémy Genoud, Hugo De Oliveira, Antoine Pierre Emmanuel Alexis Merle, Antoine Baillod, Joan Decker, Cedric Kar-Wai Tsui, Pedro Andres Molina Cabrera, Umar Sheikh, Cristian Galperti, Marcelo Baquero Ruiz, Aylwin Iantchenko, Mengdi Kong, Francesco Carpanese, Federico Pesamosca, Olivier Claude Martin Février, Simon Van Mulders, Nicola Offeddu, Garance Hélène Salomé Durr-Legoupil-Nicoud, Maurizio Giacomin, Filippo Bagnato, Davide Galassi, Arsène Stéphane Tema Biwole, Lorenzo Martinelli, , , , , , , , , , , , , , , , , , , , , , , ,

FENNECS: a novel particle-in-cell code for simulating the formation of magnetized non-neutral plasmas trapped by electrodes of complex geometries

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

This paper presents the new 2D electrostatic particle -in -cell code FENNECS developed to study the formation of magnetized non -neutral plasmas in geometries with azimuthal symmetry. This code has been developed in the domain of gyrotron electron gun desi ...

2024

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

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

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

Plasma sputtering of biased electrodes in an oblique magnetic field

Stefano Alberti, Ivo Furno, Alessandro Geraldini

The surface erosion of biased electrodes immersed in a radio frequency (RF) plasma was investigated in oblique magnetic fields ranging from 0.1 T to 3.5 T. The plasma potential and density in the vicinity of the biased electrode have been measured using an ...

IOP Publishing Ltd2023

First self-consistent simulations of trapped electron clouds in a gyrotron gun and comparison with experiments

Stefano Alberti, Jean-Philippe Hogge, Joaquim Loizu Cisquella, Ioannis Pagonakis, Jérémy Genoud, Francesco Romano

We report on the initial validation of the novel code FENNECS, which simulates the spontaneous formation of trapped electron clouds in coaxial geometries with strong externally applied azimuthal flows and in the presence of a residual neutral gas. For this ...

American Institute of Physics (AIP)2023

Homogenous power distribution along gyrotron collector walls

Stefano Alberti, Damien Fasel, Pierre-François Isoz, Jean-Philippe Hogge, Ugo Siravo, Jérémie Dubray, 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

Homogenous power distribution along gyrotron collector walls

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

2023

A new 3MW ECRH system at 105 GHz for WEST*

Stefano Alberti, Timothy Goodman, Jean-Philippe Hogge, Ioannis Pagonakis, Konstantinos Avramidis

The aim of the WEST experiments is to master long plasma pulses (1000s) and expose ITER-like tungsten wall to deposited heat fluxes up to 10 MW/m2. To increase the margin to reach the H-Mode and to control W-impurities in the plasma, the installation of an ...

2023

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

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

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

Overview of the TCV tokamak experimental programme

Patrick Blanchard, Stephan Brunner, Stefano Alberti, Basil Duval, Ambrogio Fasoli, Timothy Goodman, Xavier Llobet, Yves Martin, Jean-Marc Moret, Olivier Sauter, Henri Weisen, Ivo Furno, Holger Reimerdes, Jean-Philippe Hogge, Jan Horacek, Alexander Karpushov, Laurie Porte, Yanis Andrebe, Jonathan Graves, Duccio Testa, Benoît Labit, Joaquim Loizu Cisquella, Paolo Ricci, Christian Gabriel Theiler, Federico Alberto Alfredo Felici, Miguel Filipe Silva Füglister, Antoine Pierre Emmanuel Alexis Merle, Oulfa Chellaï, Curdin Tobias Wüthrich, Joan Decker, Cedric Kar-Wai Tsui, Pedro Andres Molina Cabrera, Matteo Fontana, Umar Sheikh, Cristian Galperti, Marcelo Baquero Ruiz, Dahye Choi, Aylwin Iantchenko, Mengdi Kong, Roberto Maurizio, Francesco Carpanese, , , , , , , , , , , , , , , , , , , , , , ,

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

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

Development of Kilowatt THz Gyrotrons for Pulsed Dynamic Nuclear Polarization - Cavity Design Code Phaedra -

Stefano Alberti, Jean-Philippe Hogge, Jérémy Genoud

A significant effort has recently been initiated at ETHZ for the development of high frequency, high power, frequency-agile gyrotrons for DNP-NMR spectroscopy. In this context an in house cavity interaction code is under development. In this paper, some de ...

IEEE2022

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

Th1509U European 170 Ghz 1 Mw Cw Industrial Gyrotron Upgrade

Stefano Alberti, Jean-Philippe Hogge, Francisco Sanchez, Ioannis Pagonakis, Konstantinos Avramidis

This paper describes the status on the upgrade of the first European gyrotron prototype for ITER, manufactured by Thales. The upgraded prototype, TH1509U, is now being tested to verify the performance improvements and to assess the compliance with ITER ECR ...

IEEE2021

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

Stefano Alberti, Francisco Sanchez, Konstantinos Avramidis

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

TCV heating and divertor upgrades

Stefano Alberti, Basil Duval, Ambrogio Fasoli, Jean-Marc Moret, Holger Reimerdes, Alexander Karpushov, Christian Gabriel Theiler, 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

Stefano Alberti, Damien Fasel, Timothy Goodman, Jean-Philippe Hogge, 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

Linear studies of spurious backward-wave instabilities in a dielectric-loaded smooth-wall gyrotron beam ducts

Stefano Alberti, Jean-Philippe Hogge, Jérémy Genoud

Recently developed self-consistent models for beam-wave interaction simulations of a gyrotron oscillator have been extended to study spurious backward-wave instabilities in smooth-wall circular symmetric beam ducts. Starting from a purely metallic case, th ...

IEEE2020