Complementary Countermeasures for Detecting Scenic Face Spoofing Attacks

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Combined high-fusion performance and long-pulse operation is one of the key integration challenges for fusion energy development in magnetic devices. Addressing these challenges requires an integrated vision of physics and engineering aspects with the purpose of simultaneously increasing time duration and fusion performance. Since the previous 2023 IAEA Fusion Energy Conference, significant progresses have been made in tokamaks and stellarators including very recent achievement in duration and/or performanc

The simulation of turbulence in the boundary region of a tokamak is crucial for understanding and optimizing the performance of fusion reactors. Solving a kinetic model for neutral particles deterministically using the method of characteristics invokes the solution of integral equations. Upon discretization, this requires the solution of dense, computationally expensive linear systems. This work employs low-rank linear algebra techniques to address this issue. In particular, we use hierarchical matrix appro

The research programme performed on the Mega Amp Spherical Tokamak (MAST) Upgrade experiment has made significant advances in developing the physics understanding of low aspect ratio tokamaks in support of the operation of ITER and design of fusion powerplants. High performance plasma scenarios have been developed to facilitate a broad programme of experiments, in which confinement is constrained by the presence of m/n = 2/1 modes that cause substantial losses of fast ions. The onset of these modes coincide

Negative triangularity plasma configurations have been extensively studied in the Tokamak à Configuration Variable (TCV), and have displayed enhanced heat confinement for thermal electrons and ions. Herein, the question of fast-ion confinement is addressed. Limited negative (NT) and positive triangularity (PT) plasmas are compared. The plasma volume and position are kept the same between the discharges to match the neutral beam heating (NBI) deposition, isolating the effect of triangularity. These plasmas w

The demand for megawatt-class gyrotrons for Electron Cyclotron Resonance Heating (ECRH) of nuclear fusion devices is growing significantly. It goes hand in hand with growing requirements for output power, efficiency, operating flexibility, and reliability of gyrotrons used in nuclear fusion, as well as higher demanding of the manufacturability for serial production. In Europe research and development is ongoing to fulfil that future needs, particularly, with regards to output power and efficiency. It is com

Nuclear fusion offers a promising route toward a clean and abundant energy source, though harnessing its potential remains an important scientific and engineering challenge. This thesis delves into one of the main challenges of fusion, namely managing the high heat fluxes exhausted from the plasma core. The understanding of scrape-off layer and divertor physics, which define how this heat load will be transported towards the reactor walls, is of crucial importance for the achievement of future reliable ther

The safe control and dissipation of Runaway Electrons (REs) generated in tokamak plasmas is vital for the operation of future fusion reactors. Measuring the evolution of RE energy in tokamaks is important for understanding their generation, transport, and termination. A new gamma ray spectrometer using a 2″ × 2″ cylindrical, cerium doped lanthanum bromide (LaBr3:Ce) scintillator coupled to a fast photomultiplier tube was developed for studying runaway electrons on the Tokamak à Configuration Variable (TCV).

The scrape-off layer (SOL) sets the bounday conditions of a tokamak, determining the plasma confinement, the heat exhaust, the impurity levels, and controlling the fuelling of the device. Therefore, a first principles understanding of the physical mechanisms governing SOL turbulence is crucial on the way towards fusion energy. We describe SOL simulations carried out by using GBS, a three-dimensional numerical code that solves the drift-reduced Braginskii equations for the two-fluid model of the plasma and c

Intermittent blobs, which propagate across a confining magnetic fields, are universally observed in natural and laboratory plasmas. In fusion plasmas, cross-field transport of particles and energy are associated, at least in part, with the propagation of blobs, which are therefore of great importance for the design of future fusion reactors. In TORPEX, blobs are generated from ideal interchange modes and, driven by B and curvature-induced charge separation, propagate radially outwards. An analytical blob s

A key issue for steady-state tokamak operation is to determine the edge conditions that are compatible both with good core confinement and with the power handling and plasma exhaust capabilities of the plasma facing components (PFCs) and divertor systems. A quantitative response to this open question will provide a robust scientific basis for reliable extrapolation of present regimes to an ITER compatible steady-state scenario. In this context, the JET programme addressing steady-state operation is focused

Current profile tailoring has been performed by application of electron cyclotron heating (ECH) and electron cyclotron current drive, leading to improved energy confinement in the plasma core of the TCV tokamak. The improved confinement is characterized by a substantial enhancement (H-factor) of the global electron energy confinement time relative to the prediction of the RLW scaling law (Rebut P H et al 1989 Proc. 12th Int. Conf. of Plasma Physics and Controlled Fusion Research (Nice, 1988) vol 2 (Vienna:

Recent progress in the Large Helical Device (LHD) experiment during the last 2 yr is reviewed. The LHD has been extending its operational regime toward fusion-relevant conditions while taking advantage of the net-current-free heliotron concept employing a superconducting coil system. Heating capability has exceeded 10 MW, and the central ion and electron temperatures have reached 7 and 10 keV respectively. The maximum values of beta and pulse length have been extended to 3.2% and 150 s, respectively. Severa

Gyrotrons at high frequency with high-output power are mainly developed for microwave heating and current drive in plasmas for thermonuclear fusion. For the stellarator Wendelstein 7-X, now under construction at IPP Greifswald, Germany, a 10-MW electron-cyclotron-resonance-heating (ECRH) system is foreseen. A 1-MW 140-GHz gyrotron with synthetic diamond window for continuous wave operation and with a single stage depressed collector for energy recovery and improvement of efficiency has been designed, constr

Long timescale density peaking has been observed in JET plasmas leading to densities exceeding the Greenwald value. These neutral beam heated discharges are characterized by type-I ELMS and good energy confinement. Central density is limited by neoclassical tearing modes or by termination of H-mode preceded by loss of sawteeth. When these limiting factors are avoided (i.e. at intermediate power level and With optimization of gas puffing) quasi-stationary high density plasmas with peaked density profile are

Current profile tailoring by electron cyclotron heating (ECH) and current drive (ECCD) is used to improve central electron energy confinement in the TCV tokamak. Counter-ECCD on axis alone achieves this goal in a transient manner only. A stable scenario is obtained by a two-step sequence of err-axis ECH, which stabilizes magnetohydrodynamics modes, and on-axis counter-ECCD, which generates a flat or inverted current profile. This high-confinement regime, with central temperatures up to 9 keV (at a. normaliz

Leading long term considerations for choices in the European Long Term Technology programme are the high temperature mechanical- and compatibility properties of structural materials under neutron irradiation. The degrees of fabrication process freedom are closely investigated to allow the construction of complex shapes. Another important consideration is the activation behaviour of the structural material. The ideal solution is the recycling of the structural materials after a relatively short 'cooling' per

Experiments with high-power electron cyclotron heating (ECH) and current drive (ECCD) in the TCV tokamak are discussed. Power up to 2.7 MW from six gyrotrons is delivered to the tokamak at the second-harmonic frequency (82.7 GHz) in X-mode. The power is transmitted to the plasma by six independent launchers, each equipped with steerable mirrors that allow a wide variety of injection angles in both the poloidal and toroidal directions. Fully non-inductive operation of the tokamak has been achieved in steady

Alfven eigenmodes (AEs) with intermediate toroidal mode numbers are modelled using the global gyrokinetic PENN code to determine the stability of high performance tokamak discharges in the presence of energetic particles. A large plasma pressure and a weak magnetic shear in the core give rise to radially extended kinetic AEs, which are stabilized by the high shear at the edge of a divertor (X point) configuration. Large values for the safety factor and the ion Larmor radius in reversed shear operation may h

Ion and electron temperatures of up to 5 keV have been obtained within 10 cm of the last closed flux surface (LCFS) in hot ion H-modes with 18 MW of neutral beam heating. The ion temperature profiles appear to have 'pedestals' which scale with power per particle, T(i)(a) less-than-or-similar-to P(a)/n(e)(0.9a) [keV, MW/10(19) m-3], in H-modes. In L-modes the pedestal temperatures are an order of magnitude lower. This difference can be explained by the one order of magnitude difference in particle residence

Complementary Countermeasures for Detecting Scenic Face Spoofing Attacks

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Investigating long-duration plasma operation with the international multi-machine CICLOP database

Accelerated Solvers for Neutral Particle Dynamics in Plasma Simulation

Overview of the MAST Upgrade physics programme: testing novel concepts at low aspect ratio to inform future devices

Fast ion confinement in negative triangularity plasmas on the TCV tokamak

Megawatt-Class Sub-THz Gyrotrons for ECRH in Future High-Field Fusion Devices

Performance assessment of a reactor-scale tightly baffled divertor using the SOLPS-ITER software

A lanthanum bromide detector of runaway electrons for TCV

Plasma refuelling at the SOL simulated with the GBS code

Understanding and taming plasma blobs in toroidal magnetized plasmas

Development of steady-state scenarios compatible with ITER-like wall conditions

Control of electron internal transport barriers in TCV

Review on the progress of the LHD experiment

Advanced high-power gyrotrons

Long timescale density peaking in JET

Long-pulse improved central electron confinement in the TCV tokamak with electron cyclotron heating and current drive

European structural materials development for fusion applications

High-power ECH and fully non-inductive operation with ECCD in the TCV tokamak

Stability of Alfven eigenmodes in optimized tokamaks

Boundary Ion Temperatures and Ion Orbit Losses in Jet