Publications related to Electron trapping mechanisms in magnetron injection guns

Magnetism of Single Surface Adsorbed Atoms Studied with Radio-Frequency STM

This thesis investigates the magnetic properties of single atoms and molecules adsorbed on thin magnesium oxide decoupling layers, grown on a silver single crystal. To address these systems experimentally, we use a low temperature scanning tunneling micros ...

EPFL2024

Re-design of EU DEMO with a low aspect ratio

Hartmut Zohm

The design point that had been chosen for EU DEMO in 2016 is reviewed here and a modification is proposed with a lower aspect ratio. Previously the same aspect ratio, A, was chosen for EU DEMO as in major tokamak experiments including ITER (A = 3.1), and, ...

2024

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

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

Stefano Alberti, Jean-Philippe Hogge, Ioannis Pagonakis, Joaquim Loizu Cisquella, 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

A reduced-order, rotation-based model for thin hard-magnetic plates

Pedro Miguel Nunes Pereira de Almeida Reis, Dong Yan, Bastien Freddy Gustave Aymon

We develop a reduced-order model for thin plates made of hard magnetorheological elastomers (hard-MREs), which are composed of hard-magnetic particles embedded in a polymeric matrix. First, we propose a new magnetic potential, as an alternative to an exist ...

PERGAMON-ELSEVIER SCIENCE LTD2023

Positive Streamer Initiation in SF6/CO2 Based on Zener's Field Ionization

Guang-Yu Sun

In this study, experiments were performed to measure the inception and breakdown voltages of SF6/CO2 mixed gases with varying mixing ratios at two different pressures (1 and 2 bar). Using the preliminary data obtained from the experiments, a 3D particle mo ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2023

Direct observation of exchange anisotropy in the helimagnetic insulator Cu2OSeO3

Arnaud Magrez, Priya Ranjan Baral, Jonathan White, Chen Luo

The helical magnetic structures of cubic chiral systems are well explained by the competition among Heisen-berg exchange, Dzyaloshinskii-Moriya interaction, cubic anisotropy, and anisotropic exchange interaction (AEI). Recently, the role of the latter has ...

AMER PHYSICAL SOC2023

Investigation of the interplay between Electron-Cyclotron waves, suprathermal electrons and turbulence in tokamak plasmas

Jean Arthur Cazabonne

Electron-Cyclotron waves are routinely used in tokamaks to heat the plasma and to drive current through the electron channel. Their unique ability to drive very localized current renders them the main foreseen tool for neoclassical tearing mode mitigation ...

EPFL2023

Adaptive Symplectic Model Order Reduction Of Parametric Particle-Based Vlasov-Poisson Equation

Jan Sickmann Hesthaven, Nicolò Ripamonti, Cecilia Pagliantini

. High-resolution simulations of particle-based kinetic plasma models typically require a high number of particles and thus often become computationally intractable. This is exacerbated in multi-query simulations, where the problem depends on a set of para ...

AMER MATHEMATICAL SOC2023

Magnetic excitations in the topological semimetal YbMnSb2

Jian Rui Soh

We report neutron scattering measurements on YbMnSb2 which shed light on the nature of the magnetic moments and their interaction with Dirac fermions. Using half-polarized neutron diffraction we measured the field-induced magnetization distribution in the ...

AMER PHYSICAL SOC2023