Publications related to Generation of highly confined optical bottle beams by exploiting the photonic nanojet effect

Divertor turbulence characterisation using Gas Puff Imaging in the TCV tokamak

The performance of magnetic confinement fusion devices, such as tokamaks, is strongly correlated to the phenomena that occur in the boundary region of the plasma core that faces the wall of the device. The dominant cross-field transport mechanisms from the ...

EPFL2024

3D Characterisation of Turbulent Plasma Filaments Using Gas Puff Imaging in the Tokamak à Configuration Variable

Nicola Offeddu

A key challenge for the development of fusion reactors based on magnetic confinement, such as tokamaks and stellarators, is the control of the turbulent processes. The most prominent feature of turbulence in the Scrape-Off Layer (SOL), the volume between t ...

EPFL2023

An experimental and computational study of tokamak plasma turbulence

Aylwin Iantchenko

Turbulence driven by small-scale instabilities results in strong heat and particle transport, which significantly shortens the confinement time and prevents the formation of a self-sustained plasma reaction in magnetic confinement devices. Control and poss ...

EPFL2023

How accurate are flux-tube (local) gyrokinetic codes in modeling energetic particle effects on core turbulence?

Olivier Sauter, Alberto Bottino, Emanuele Poli

Flux-tube (local) gyrokinetic codes are widely used to simulate drift-wave turbulence in magnetic confinement devices. While a large number of studies show that flux-tube codes provide an excellent approximation for turbulent transport in medium-large devi ...

IOP Publishing Ltd2023

The competing effects of wave amplitude and collisions on multi-ion species suppression of stimulated Brillouin scattering in inertial confinement fusion Hohlraums

Stephan Brunner

Reduction in stimulated Brillouin scattering (SBS) from National Ignition Facility Hohlraums has been predicted through the use of multi-ion species materials on Hohlraum walls. This approach to controlling SBS is based upon introducing a lighter ion speci ...

2023

Electron temperature fluctuation measurements with Correlation Electron Cyclotron Emission in L-mode and I-mode plasmas at ASDEX Upgrade

Pedro Andres Molina Cabrera

The Correlation Electron Cyclotron Emission (CECE) diagnostic at ASDEX Upgrade (AUG) is used to investigate the features of outer core and pedestal (rho(pol) = 0.85-1.0) turbulence across confinement regime transitions. The I-mode confinement regime is a p ...

E D P SCIENCES2023

Tracking blobs in the turbulent edge plasma of a tokamak fusion device

Christian Gabriel Theiler, Nicola Offeddu, Woonghee Han

The analysis of turbulence in plasmas is fundamental in fusion research. Despite extensive progress in theoretical modeling in the past 15 years, we still lack a complete and consistent understanding of turbulence in magnetic confinement devices, such as t ...

Nature Portfolio2022

Approaching detachment in I-mode-response of core confinement and the edge pedestal in the ASDEX Upgrade tokamak

Antoine Pierre Emmanuel Alexis Merle

Experiments on nitrogen assisted divertor detachment in the improved energy confinement mode (I-mode) are reported from the ASDEX Upgrade tokamak. When nitrogen is introduced into the divertor and radiation losses cool the divertor plasma down, a loss of c ...

IOP Publishing Ltd2021

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

Studying the effect of non-adiabatic passing electron dynamics on microturbulence self-interaction in fusion plasmas using gyrokinetic simulations

Ajay Chandrarajan Jayalekshmi

Microturbulence driven by plasma instabilities is in most cases the dominant cause of heat and particle loss from the core of magnetic confinement fusion devices and therefore presents a major challenge in achieving burning plasma conditions. The role of p ...

EPFL2020

Ultra-compact spoof surface plasmon polariton waveguides and notch filters based on double-sided parallel-strip lines

Longfang Ye

In this paper, we propose a new variety of strong field confinement, ultra-compact size, easy-to-integrate spoof surface plasmon polariton (SSPP) waveguides based on double-sided parallel-strip lines (DSPSL), which are formed by etching opposite spiral gro ...

2020

H-mode grade confinement in L-mode edge plasmas at negative triangularity on DIII-D

Olivier Sauter, Alessandro Marinoni, Sung Chul Park

Plasmas with a negative triangularity shape have been created on the DIII-D tokamak that, despite maintaining standard L-mode edge radial profiles, reach volume averaged pressure levels typical of H-mode scenarios. Within the auxiliary power available for ...

2019

Effects of collisionality and T e /T i on fluctuations in positive and negative δ tokamak plasmas

Stephan Brunner, Ambrogio Fasoli, Olivier Sauter, Stefano Coda, Laurie Porte, Gabriele Merlo, Matteo Fontana, Ajay Chandrarajan Jayalekshmi

The effects of negative triangularity () on confinement and fluctuations in plasmas covering a large range of parameters were investigated on the tokamak à configuration variable (TCV). The conditions explored in this paper include discharges where neutral ...

IOP Publishing Ltd2019

Physics and performance of the I-mode regime over an expanded operating space on Alcator C-Mod

Christian Gabriel Theiler, Yu Lin

New results on the I-mode regime of operation on the Alcator C-Mod tokamak are reported. This ELM-free regime features high energy confinement and a steep temperature pedestal, while particle confinement remains at L-mode levels, giving stationary density ...

IOP Publishing Ltd2017

Fast particle loss channels in Wendelstein 7-X

Wilfred Anthony Cooper, Jonathan Graves, David Pfefferlé, Jonathan Marc Philippe Faustin

One of the main goals of Wendelstein 7-X (W7-X) is to demonstrate the fast particle confinement properties of the quasi-isodynamic stellarator concept. Fast particle populations will be produced either by Neutral Beam Injection (NBI) or by minority Ion Cyc ...

Nuclear Fusion2016

Overview of MAST results

Wilfred Anthony Cooper, Ricardo Pérez Suárez, Jan Horacek, Jonathan Graves, Mario Ludovico Podesta, Ben McMillan, Otto Asunta

The Mega Ampere Spherical Tokamak (MAST) programme is strongly focused on addressing key physics issues in preparation for operation of ITER as well as providing solutions for DEMO design choices. In this regard, MAST has provided key results in understand ...

Iop Publishing Ltd2015

Counterpropagating Rossby waves in confined plane wakes

François Gallaire, Luca Biancofiore

In the present work, we revisit the temporal and the spatio-temporal stability of confined plane wakes under the perspective of the counterpropagating Rossby waves (CRWs). Within the context of broken line velocity profiles, each vorticity discontinuity ca ...

American Institute of Physics2012

On the Characteristics of Highly Confined Light Fields : A High-Resolution Interference Microscopy Study

Myun Sik Kim

The Investigation of highly confined light fields created by different mechanisms, such as refraction, diffraction, and scattering, are the main subject of this thesis. We distinguish a specific scattering phenomenon of dielectric microspheres from general ...

EPFL2011

Correcting spherical aberrations induced by an unknown medium through determination of its refractive index and thickness

Pramod Rastogi, Daniel Iwaniuk

In imaging and focusing applications, spherical aberration induces axial broadening of the point spread function (PSF). A transparent medium between lens and object of interest induces spherical aberration. We propose a method that first obtains both the p ...

Optical Society of America2011

Modeling and control of the current density profile in tokamaks and its relation to electron transport

Costanza Zucca

The current density in tokamak plasmas strongly affects transport phenomena, therefore its understanding and control represent a crucial challenge for controlled thermonuclear fusion. Within the vast framework of tokamak studies, three topics have been tac ...

EPFL2009