Publications related to Moment-based, self-consistent linear analysis of gyrotron oscillators

Modelling of nonneutral plasmas trapped by electric and magnetic fields relevant to gyrotron electron guns

Gyrotrons are a class of high-power vacuum-electronics microwave sources, which are envisioned to play an important role in the domain of magnetically confined fusion plasmas. Indeed, only gyrotrons are capable of producing continuous electromagnetic waves ...

EPFL2023

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

Experimental Testing of the European TH1509U 170-GHz 1-MW CW Industrial Gyrotron-Long Pulse Operation

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

The upgraded European 1-MW, 170-GHz continuous wave (CW) industrial prototype gyrotron (TH1509U) for electron cyclotron resonance heating and current drive in ITER was tested at the Karlsruhe Institute of Technology (KIT). In this work, we report on the ma ...

Institute of Electrical and Electronics Engineers2022

Prototype mitre bends of the ex-vessel waveguide system for the ITER upper launcher: Thermal hydraulic simulations and experiments with off-center mm-wave beams

René Chavan, Timothy Goodman, Matteo Vagnoni, Anastasia Xydou, Humberto Torreblanca Quiroz

On ITER, long pulse gyrotrons are required as a power source for electron cyclotron heating (ECH) and current drive (CD). The microwaves are guided from the gyrotrons, which are placed far from the Tokamak, into the plasma by transmission lines (TLs) and a ...

2021

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

Megawatt power generation of the dual-frequency gyrotron for TCV at 84 and 126 GHz, in long pulses

Stefano Alberti, Damien Fasel, Timothy Goodman, Blaise Marlétaz, Minh Quang Tran, Jean-Philippe Hogge, Ugo Siravo, Christian Moura, Jérémie Dubray, Ioannis Pagonakis, Jonathan Sylvain Masur, Matthieu Toussaint, Jérémy Genoud, Konstantinos Avramidis

In the frame of the TCV Tokamak upgrade, two 84/126 GHz/2 s dual frequency gyrotrons designed by SPC and KIT and manufactured by THALES will be added to the existing EC-System. The first unit has been delivered to EPFL-SPC and tested. In the commissioning ...

2020

Coss Loss Tangent of Field-Effect Transistors: Generalizing High-Frequency Soft-Switching Losses

Elison de Nazareth Matioli, Armin Jafari, Palliyage Srilak Nirmana Perera, Mohammad Samizadeh Nikooytabalvandani, Luca Nela

The dissipated energy (Ediss) related to the resonant charging/discharging of a transistor output capacitance, becomes a dominant loss factor for power converters operating in the MHz range. A recent work has introduced a small-signal measurement method to ...

2020

Advanced linear models for gyro-backward wave instabilities in gyrotrons

Jérémy Genoud

Parasitic oscillations excitation is one of the main point hindering high-power gyrotron operation for fusion application. These instabilities, besides being dangerous for the gyrotron components, could possibly degrade the electron beam quality before it ...

EPFL2019

Metrology techniques for the verification of the alignment of the EU gyrotron prototype for ITER

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

The EU gyrotron for the ITER Electron Cyclotron (EC) heating system has been developed in coordinated efforts of the EGYC Consortium, Thales ED (TED) and Fusion for Energy (F4E) and under the supervision of ITER Organization Central Team. After the success ...

E D P SCIENCES2019

Modeling of parasitic oscillations in smooth-wall circular symmetric dielectric-loaded gyrotron beam ducts

Stefano Alberti, Jean-Philippe Hogge, Jérémy Genoud

The self-consistent simulation of the electron beam interaction was performed in the presence of a lossy dielectric layer in the smooth-wall beam duct of a gyrotron oscillator. For this purpose, the linear and spectral code TWANGlinspec was extended. In th ...

AMER INST PHYSICS2019

Report of recent experiments with the European 1 MW, 170 GHz CW and SP prototype gyrotrons for ITER

Stefano Alberti, Minh Quang Tran, Jean-Philippe Hogge, Christian Schlatter, Francisco Sanchez, Ioannis Pagonakis, Konstantinos Avramidis, Martin Schmid

The European 1 MW, 170 GHz industrial CW prototype gyrotron has been designed within EGYC (European GYrotron Consortium) in collaboration with the industrial partner Thales Electron Devices (TED) and under the coordination of Fusion for Energy (F4E). This ...

E D P SCIENCES2019

Diamond Window Technology for Electron Cyclotron Heating and Current Drive: State of the Art

Konstantinos Avramidis

Nuclear fusion power plants require electron cyclotron (EC) heating and current drive (H&CD) systems for plasma heating and stabilization. High-power microwave beams between 1 and 2?MW generated by gyrotrons propagate in a dedicated waveguide transmission ...

TAYLOR & FRANCIS INC2019

Design and implementation of quasi-optical components for the upgrade of the TCV EC-system

Stefano Alberti, Timothy Goodman, Jean-Philippe Hogge, Laurie Porte, Matthieu Toussaint, Florian Ramseyer

The EC-system of the TCV tokamak is progressively being upgraded with the addition of two MW-class dual-frequency gyrotrons (84 and 126 GHz/2s/1MW). In order to connect the two gyrotrons to the existing low field side and top launchers, new waveguide routi ...

ELSEVIER SCIENCE SA2019

High-power gyrotrons for electron cyclotron heating and current drive

Minh Quang Tran

In many tokamak and stellarator experiments around the globe that arc investigating energy production via controlled thermonuclear fusion, electron cyclotron heating and current drive (ECH&CD) are used for plasma start-up, heating, non-inductive current dr ...

IOP Publishing Ltd2019

Overview of recent gyrotron R&D towards DEMO within EUROfusion Work Package Heating and Current Drive

Jean-Philippe Hogge, Ioannis Pagonakis, Jérémy Genoud, Konstantinos Avramidis, Martin Schmid

Gyrotron R&D within the EUROfusion Work Package Heating and Current Drive (WPHCD) is addressing the challenging requirements posed on gyrotrons by the European concept for a demonstration fusion power plant (EU DEMO). These requirements, as specified withi ...

IOP Publishing Ltd2019

From W7-X Towards ITER and Beyond: 2019 Status on EU Fusion Gyrotron Developments

Stefano Alberti, Damien Fasel, Blaise Marlétaz, Jean-Philippe Hogge, Jérémie Dubray, Ioannis Pagonakis, Jérémy Genoud, Konstantinos Avramidis

In Europe, the research and development with main focus on achieving robust industrial designs of series gyrotrons for electron cyclotron heating and current drive of today's nuclear fusion experiments and towards a future DEMOnstration fusion power plant ...

IEEE2019

Multimode microwave circuit optomechanics as a platform to study coupled quantum harmonic oscillators

Nathan Rafaël Bernier

Harmonic oscillators might be one of the most fundamental entities described by physics. Yet they stay relevant in recent research. The topological properties associated with exceptional points that can occur when two modes interact have generated much int ...

EPFL2019

Recent experiments with the European 1MW, 170GHz industrial CW and short-pulse gyrotrons for ITER

Stefano Alberti, Minh Quang Tran, Jean-Philippe Hogge, Christian Schlatter, Francisco Sanchez, Ioannis Pagonakis, Jérémy Genoud, Konstantinos Avramidis

The European Gyrotron Consortium (EGYC) is developing the European 1 MW, 170 GHz Continuous Wave (CW) industrial prototype gyrotron for ITER in cooperation with Thales Electron Devices (TED) and Fusion for Energy (F4E). This conventional, hollow-cavity gyr ...

ELSEVIER SCIENCE SA2019

Tests and developments of a long-pulse high-power 170 GHz absorbing matched load

Stefano Alberti, Damien Fasel, Timothy Goodman, Jean-Philippe Hogge, Francesca Maria Poli, Francisco Sanchez, Ioannis Pagonakis

The future EC systems will consist of several gyrotron sources providing MW-level millimeter wave power at a frequency around or above 170 GHz. The development of matched loads is necessary to test the new sources, the components for the transmission lines ...

ELSEVIER SCIENCE SA2019

Enhanced operation of the Eu Ec test facility

Stefano Alberti, Damien Fasel, Timothy Goodman, Albert Perez, Jean-Philippe Hogge, Ugo Siravo, Jérémie Dubray

A Test Facility (TF) has been designed and installed at SPC to allow for the commissioning of the EU gyrotrons developed in view of their integration to the ITER EC system. The first phase of operation of this TF was dedicated to the development of the EU ...

ELSEVIER SCIENCE SA2019