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

Publications associées (54)

Localized model order reduction and domain decomposition methods for coupled heterogeneous systems

Jan Sickmann Hesthaven, Niccolo' Discacciati

We propose a model order reduction technique to accurately approximate the behavior of multi-component systems without any a-priori knowledge of the coupled model. In the offline phase, we construct independent surrogate models by solving the local problem ...

Wiley2023

Uncertainty-aware Flexibility Envelope Prediction in Buildings with Controller-agnostic Battery Models

Colin Neil Jones, Rafael Eduardo Carrillo Rangel, Paul Scharnhorst

Buildings are a promising source of flexibility for the application of demand response. In this work, we introduce a novel battery model formulation to capture the state evolution of a single building. Being fully data-driven, the battery model identificat ...

IEEE2023

Estimating the Topology of Preferential Attachment Graphs Under Partial Observability

Ali H. Sayed

This work addresses the problem of learning the topology of a network from the signals emitted by the network nodes. These signals are generated over time through a linear diffusion process, where neighboring nodes exchange messages according to the underl ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2023

Nanomechanical resonators with low dissipation for quantum optomechanics

Alberto Beccari

Fields of technology as diverse as microwave filter construction, characterization of material interfaces with atomic precision, and detection of gravitational waves from astronomical sources employ mechanical resonators at their core. The utility of mecha ...

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

Visualizing Interfacial Energy Offset and Defects in Efficient 2D/3D Heterojunction Perovskite Solar Cells and Modules

Mohammad Khaja Nazeeruddin, Paul Joseph Dyson, Bin Ding, Yong Ding

Currently, the full potential of perovskite solar cells (PSCs) is limited by chargecarrier recombination owing to imperfect passivation methods. Here, the recombination loss mechanisms owing to the interfacial energy offset and defects are quantified. The ...

Wiley-V C H Verlag Gmbh2023

Spin wave dispersion of ultra-low damping hematite (α-Fe2O3) at GHz frequencies

Dirk Grundler, Ferdinand Rémy Hynek Posva, Mohammad Hamdi

Raw data associated to the manuscript ‘’Spin wave dispersion of ultra-low damping hematite (α-Fe2O3) at GHz frequencies‘’, Physical Review Materials 7, 054407(2023); doi: 10.1103/PhysRevMaterials.7.054407 Information about file fo ...

Zenodo2023

Spin wave dispersion of ultra-low damping hematite ( α−Fe2O3 ) at GHz frequencies

Dirk Grundler, Ferdinand Rémy Hynek Posva, Mohammad Hamdi

Low magnetic damping and high group velocity of spin waves (SWs) or magnons are two crucial parameters for functional magnonic devices. Magnonics research on signal processing and wave-based computation at GHz frequencies focused on the artificial ferrimag ...

2023

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

Guillaume Michel Le Bars

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

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

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

Individual Barkhausen Pulses of Ferroelastic Nanodomains

Dragan Damjanovic, Vasiliki Tileli, Reinis Ignatans

Ferroelectric materials, upon electric field biasing, display polarization discontinuities known as Barkhausen jumps, a subclass of a more general phenomenon known as crackling noise. Herein, we follow at the nanoscale the motion of 90 degree needle domain ...

2021

Photonic microwave generation in the X- and K-band using integrated soliton microcombs

Rui Ning Wang, Tobias Kippenberg, Johann Emmeram Riemensberger, Erwan Guillaume Albert Lucas, Maxim Karpov, Hairun Guo, Junqiu Liu, Arslan Sajid Raja, Romain Dany Bruno Bouchand, Jijun He

Microwave photonic technologies, which upshift the carrier into the optical domain, have facilitated the generation and processing of ultra-wideband electronic signals at vastly reduced fractional bandwidths. For microwave photonic applications such as rad ...

Nature Publishing Group2020

Small Obstacle in a Large Polar Flock

Ignacio Pagonabarraga Mora

We show that arbitrarily large polar flocks are susceptible to the presence of a single small obstacle. In a wide region of parameter space, the obstacle triggers counterpropagating dense bands leading to reversals of the flow. In very large systems, these ...

AMER PHYSICAL SOC2022

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

Three-dimensional Fermi surfaces from charge order in layered CsV3Sb5

Yi-Chiang Sun, Xiangwei Huang, Philip Johannes Walter Moll, Matthias Carsten Putzke, Chunyu Guo

The cascade of electronic phases in CsV3Sb5 raises the prospect to disentangle their mutual interactions in a clean, strongly interacting kagome lattice. When the kagome planes are stacked into a crystal, its electronic dimensionality encodes how much of t ...

AMER PHYSICAL SOC2022

Simulating Microswimmers Under Confinement With Dissipative Particle (Hydro) Dynamics

Ignacio Pagonabarraga Mora

In this work we study microwimmers, whether colloids or polymers, embedded in bulk or in confinement. We explicitly consider hydrodynamic interactions and simulate the swimmers via an implementation inspired by the squirmer model. Concerning the surroundin ...

FRONTIERS MEDIA SA2022

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

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

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

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

Terbium-Doped and Dual-Passivated gamma-CsPb(I1-xBrx)(3) Inorganic Perovskite Solar Cells with Improved Air Thermal Stability and High Efficiency

Mohammad Khaja Nazeeruddin

Realizing photoactive and thermodynamically stable all-inorganic perovskite solar cells (PSCs) remains a challenging task within halide perovskite photovoltaic (PV) research. Here, a dual strategy for realizing efficient inorganic mixed halide perovskite P ...

Wiley-V C H Verlag Gmbh2022

Design of an intake and a thruster for an atmosphere-breathing electric propulsion system

Thomas Binderup Jensen, Francesco Romano

Challenging space missions include those at very low altitudes, where the atmosphere is the source of aerodynamic drag on the spacecraft, that finally defines the mission's lifetime, unless a way to compensate for it is provided. This environment is named ...

2022