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Jérémy Genoud

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Publications associées (38)

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

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

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

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

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

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

High-efficiency, long-pulse operation of MW-level dual-frequency gyrotron, 84/126GHz, for the TCV Tokamak

Stefano Alberti, Damien Fasel, Timothy Goodman, Pierre-François Isoz, Pierre Lavanchy, Blaise Marlétaz, Jean-Philippe Hogge, Ugo Siravo, Jérémie Dubray, Jonathan Sylvain Masur, Miguel Filipe Silva Füglister, Matthieu Toussaint, Jérémy Genoud

The first unit of the dual-frequency gyrotron, 84-126GHz/lMW/2s, for the upgrade of the TCV ECH system has been delivered and is presently being commissioned. During a first phase, long-pulse operation (TRF>0.5s) has been achieved and powers in excess of 0 ...

IEEE2019

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

High-Field Liquid-State Dynamic Nuclear Polarization in Microliter Samples

Stefano Alberti, Jean-Philippe Ansermet, Emile Jacques de Rijk, Jérémy Genoud

2018

Parasitic Oscillations in Smooth-Wall Circular Symmetric Gyrotron Beam Ducts

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

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

Linear and non-linear studies of spurious backward-wave instabilities in a smooth-wall gyrotron beam duct

Stefano Alberti, Trach-Minh Tran, Jérémy Genoud

Recently developed self-consistent models for beam-wave interaction simulations of a gyrotron oscillator are used to study spurious backward-wave instabilities in smooth-wall metallic beam ducts. Starting from a simple case with a basic geometry, the influ ...

2017

Novel linear analysis for a gyrotron oscillator based on a spectral approach

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

With the aim of gaining a better physical insight into linear regimes in gyrotrons, a new linear model was developed. This model is based on a spectral approach for solving the self-consistent system of equations describing the wave-particle interaction in ...

American Institute of Physics (AIP)2016

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

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

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

Progress on the upgrade of the TCV EC-system with two 1MW dual-frequency gyrotrons

Stefano Alberti, Timothy Goodman, Minh Quang Tran, Trach-Minh Tran, Jean-Philippe Hogge, Ioannis Pagonakis, Jérémy Genoud, Konstantinos Avramidis

The upgrade of the electron cyclotron (EC) system of the TCV tokamak has entered in its realization phase. The MW-class dual-frequency gyrotron design (84 or 126GHz/2s), based on the 140GHz W7-X gyrotron, is finalized and a contract for the manufacturing o ...

IEEE2016

500-fold enhancement of in situ 13C liquid state NMR using gyrotron-driven temperature-jump DNP

Stefano Alberti, Jérémy Genoud

A 550-fold increase in the liquid state C-13 NMR signal of a 50 mu L sample was obtained by first hyperpolarizing the sample at 20 K using a gyrotron (260 GHz), then, switching its frequency in order to apply 100 W for 1.5 s so as to melt the sample, final ...

Academic Press Inc - Elsevier Science2016

Generalized radiation boundary conditions in gyrotron oscillator modeling

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

A numerical procedure to implement a frequency-independent generalized non-reflecting radiation boundary conditions, GNRBC, based on the Laplace Transform, is described in details and tested successfully on a simple 2 frequency test problem. In the case of ...

Springer2015

TWANG-PIC, a novel gyro-averaged one-dimensional particle-in-cell code for interpretation of gyrotron experiments

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

A new gyrotron simulation code for simulating the beam-wave interaction using a monomode time-dependent self-consistent model is presented. The new code TWANG-PIC is derived from the trajectory-based code TWANG by describing the electron motion in a gyro-a ...

Amer Inst Physics2015

Novel self-consistent linear theory of a gyrotron oscillator and experimental validation

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

2015

Nanosecond Pulses in a THz Gyrotron Oscillator Operating in a Mode-Locked Self-Consistent Q-Switch Regime

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

An experimental study of a nanosecond pulsed regime in a THz gyrotron oscillator operating in a self-consistent Q-switch regime has been carried out. The gyrotron is operated in the TE7,2 transverse mode radiating at a frequency of 260.5 GHz. The 5 W nanos ...

Amer Physical Soc2013

High-Power THz-Waves using gyrotrons: new physics results

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

2013

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