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Fast ions have been observed to be accelerated in the presence of Edge Localised Modes (ELMs) and MHD activity on the Tokamak & aacute; Configuration Variable. The acceleration time, velocity-space and frequency dynamics have been resolved by analysing the fast-ion losses measured using a unique Fast Ion Loss Detector (FILD) that allows microsecond velocity-space mapping. The findings presented herein complement and extend previous studies done at the Asdex Upgrade Tokamak and show a decorrelation between t

Nuclear fusion is a promising long-term solution for large-scale and low-carbon energy production, relying on the confinement of high-temperature plasmas in magnetic devices such as tokamaks. Achieving and sustaining high fusion performance requires operation close to physical and technological limits, where plasma behavior becomes highly nonlinear and sensitive to perturbations. In this context, accurate real-time observation and control of plasma kinetic profiles, such as the electron density, temperature

Nuclear fusion is a clean and virtually infinite source of energy. Magnetically confined fusion based on the tokamak is the most promising approach to unleash this energy in the near feature. The current reference scenario is based on the High confinement mode (H-mode), which enables the conditions to achieve terrestrial fusion. However, this scenario is plagued by a few concerning issues that might prevent achieving such a result. In this thesis, we explore an alternative scenario, the Negative Triangulari

Erbium (Er) is an attractive gain medium for amplifiers and lasers due to its long excited-state lifetime, low noise and nonlinearity, and temperature stability. Recently developed ultra-low-loss Si 3 N 4 photonic integrated circuits combined with Er ion implantation have enabled high-performance on-chip Er lasers, but manufacturing scalability has been limited by the high 2 MeV implantation required for tightly confined 700-nm-thick waveguides. Here we demonstrate the first fully wafer-scale, foundry-compa

The high confinement regime (H-mode) is considered fundamental for high-performance operation in next-step tokamaks. It is generally characterized by the occurrence of edge localized modes (ELMs), even though several no-ELM and small-ELM regimes have extended their operational space in the past years (Viezzer et al 2023 Nucl. Mater. Energy 34 101308). The control and suppression of these modes is a priority for the development of scenarios with a confinements good enough for the ITER baseline (Sips et al 20

We report an experimental investigation of a falling water film sheared by a turbulent counter-current air flow in an inclined rectangular channel. Film thickness and wave velocity measurements associated with visual observation are conducted to study the ...

We present the results of 3D simulations of indirect drive inertial confinement fusion capsules driven by the "high-foot" radiation pulse on the National Ignition Facility. The results are post-processed using a semi-deterministic ray tracing model to gene ...

EAST has been equipped with two high power lower hybrid current drive (LHCD) systems with operating frequencies of 2.45 GHz and 4.6 GHz. Comparative LHCD experiments with the two different frequencies were performed in the same conditions of plasma for the ...

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 ...

TCV is acquiring a new 1 MW neutral beam and 2 MW additional third-harmonic electron cyclotron resonance heating (ECRH) to expand its operational range. Its existing shaping and ECRH launching versatility was amply exploited in an eclectic 2013 campaign. A ...

This work reports a simple, miniaturized optical sensing module for liquid refractometry. It is based on a stable Fabry-Perot resonator consisting of two silicon cylindrical mirrors with a cylindrical lens in the core. The lens is formed by a capillary tub ...

High-confinement mode (H-mode) is a promising reference scenario for ITER. But we are still facing major issues because of instabilities. They expel periodically some of the energy, which can damage the device. These instabilities are called the edge localized modes (ELM) and are not yet fully theoretically understood. The present work is a study on the profiles evolution in between ELMs and on the ELM effects. This may help to have a better understanding of the conditions before the ELM. We use the simulat

The tokamak à configuration variable (TCV) is unique in its ability to create a variety of plasma shapes and to heat the electron population in high density regimes using microwave power at the third harmonic of the electron cyclotron frequency. In the fra ...

In the simple magnetized torus TORPEX (R = 1 m, a = 0.2 m), we explore experimentally the accessibility of a high confinement mode, which is predicted by theory for this configuration [P. Ricci, et al., Phys. Rev. Lett. 100, 225002 (2008)]. We consider different gases (H2, D, He, Ne, N2) and we measure the dependence of the temperature and density gradients upon the ratio γ/v’ExB (γ is the interchange linear growth rate and v’ExB is the velocity shear). We observe that gamma/v’ExB decreases from γ/v’ExB~6-7

Two-dimensional (2D) photonic crystals (PhCs) at near-infrared wavelengths are promising candidates for novel integrated optics applications. The main focus being on 'all PhC' monolithically integrated optical circuits. Because of well established fabrication technologies particular emphasis is on 'quasi' 2D PhCs where a 2D lattice of air holes is etched through a planar step-index waveguide providing the optical confinement in the third dimension. This approach has been successfully demonstrated both in Ga

A new understanding of edge localized modes (ELMs) in tokamak discharges is emerging (Snyder P B et al 2002 Phys. Plasmas 9 2037), in which the ELM is an essentially ideal magnetohydrodynamic (MHD) instability and the ELM severity is determined by the radial width of the linearly unstable MHD kink modes. A detailed, comparative study of the penetration into the core of the respective linear instabilities in a standard DIII-D ELMing, high confinement mode (H-mode) discharge, with that for two relatively high

Recent experiments at the Joint European Torus [Rebut , Fusion Eng. Des. 22, 7 (1993)] aim to improve confinement quality in high-confinement-mode (H-mode) plasmas at high densities. Energy confinement time as predicted by the International Thermonuclear Experimental Reactor ITER-H98(y,2) scaling at densities near or in excess of 85% of the Greenwald density limit scaling has been obtained by (i) strong plasma shaping (triangularity 0.35

The JET experimental campaign has focused on studies in support of the ITER physics basis. An overview of the results obtained is given for the reference ELMy H mode and advanced scenarios, which in JET are based on internal transport barriers. JET studies for ELMy H mode have been instrumental in the definition of ITER FEAT. Positive elongation and current scaling in the ITER scaling law have been confirmed, but the observed density scaling fits a two term (core and edge) model better. Significant progress

The modification of turbulence in the edge plasma of the DIII-D tokamak at the transition from the low to the high mode of confinement is investigated with a phase-contrast imaging diagnostic. The amplitude and radial correlation length of the turbulence in the confinement region decrease at the transition, whereas the decorrelation time increases. The transition model of Biglari, Diamond, and Teny [Phys. Fluids B 2 (1990) 1], based on turbulence decorrelation by E x B velocity shear, is quantitatively subs

A transmission-line type of EMP simulator, consisting of two conductors with a central parallel plate region has been designed, fabricated and tested. It has been named SEMIRAMIS-I, which stands for Simulateur Electromagnetique a Impulsion Raide pour des Mesures Industrielles et Scientifiques. This simulator can be energized by either a CW or a transient pulse source. Testing was performed with ELGAL's EM-103 pulser (20 kV-100 kV, 7-9 ns risetime, 150 ns FWHM). The desired working volume is about 3 m long×1

Hohlraum

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Dynamics of the Fast-ion Acceleration in Type-i Elmy H-mode Scenarios on the Tcv Tokamak

Application of a multi-rate state observer for real-time plasma density reconstruction and control on TCV

Theoretical and experimental studies of negative triangularity tokamak plasmas and their applicability to reactor design

Wafer-scale manufacturing of ultra-broadband, high-power erbium-doped integrated lasers

Experimental characterization of inter-ELM modes in type-I ELMy scenarios at TCV using the thermal helium beam diagnostic

Characteristics of solitary waves on a falling liquid film sheared by a turbulent counter-current gas flow

Signatures of asymmetry in neutron spectra and images predicted by three-dimensional radiation hydrodynamics simulations of indirect drive implosions

Lower hybrid current drive experiments with different launched wave frequencies in the EAST tokamak

Overview of MAST results

The Science Program of the TCV Tokamak: Exploring Fusion Reactor and Power Plant Concepts

Volume refractometry of liquids using stable optofluidic Fabry-Perot resonator with curved surfaces

Theoretical study of electronic transport in TCV ELMy H-mode

Pedestal Characteristics and MHD Stability of H-Mode Plasmas in TCV

Confinement regimes in simple magnetized toroidal plasmas

Experimental and numerical investigation of two-dimensional photonic crystals for application in integrated optics

Edge localized modes in DIII-D high performance discharges

High density, high performance high-confinement-mode plasmas in the Joint European Torus (JET)

Overview of JET results in support of the ITER physics basis

Decorrelation of edge plasma turbulence at the transition from low- to high-confinement mode in the DIII-D Tokamak

SEMIRAMIS: an asymmetrical bounded wave EMP simulator with a good confinement inside the transmission line