Suprathermal electron studies in Tokamak plasmas by means of diagnostic measurements and modeling

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Plasma shape control is a fundamental tool for effective tokamak operation, allowing improved plasma performance and the pursuit of challenging scientific objectives. In this framework, the Tokamak á Configuration Variable (TCV) of the École Polytechnique ...

The quasi-continuous exhaust (QCE) regime is a type-I ELM-free high confinement regime obtained at high plasma shaping and high separatrix density. A comparison with various ELM-free regimes in the literature is presented together with potential physics mo ...

In tokamaks, rotating magneto-hydro-dynamic modes frequently decelerate as their amplitude increases. Once a critical threshold in amplitude is reached, these modes stop rotating into a specific toroidal and poloidal position and are commonly named Locked ...

The plasma density is a crucial parameter of tokamak discharge as it impacts the fusion power, stability limits, influences detachment onset and impurities transport. The electron density profile shaping affects the deposition location of the external heat ...

Helicon discharges are often considered somewhat mysterious, exhibiting experimental behaviors that are challenging to explain, such as abrupt plasma density jumps, hysteresis, and ‘blue core’ formation, among others. A significant part of the difficulty i ...

We analyze a measure for the degree of chaos in the magnetic fields of magnetic confinement fusion reactors by calculating the lobe fluxes of turnstiles - a method developed for characterizing transport into and out of resonance zones in Hamiltonian dynami ...

Plasma edge simulations with the SOLPS-ITER code are performed to study the influence of divertor baffles on nitrogen-seeded detachment in Tokamak & agrave; Configuration Variable (TCV) single-null, L-mode discharges. Scans of nitrogen seeding rate are con ...

We present a model for the particle balance in the post-disruption runaway electron plateau phase of a tokamak discharge. The model is constructed with the help of, and applied to, experimental data from TCV discharges investigating the so-called 'low-Z be ...

Nuclear fusion presents a promising clean energy source to mitigate future energy crises, with magnetic confinement fusion well-positioned to provide a baseload scenario to power future reactors. The unmitigated power exhaust of such reactors threatens its ...

We discuss how the combination of experimental observations and rapid modeling has enabled to improve understanding of the tokamak ramp-down phase in ASDEX Upgrade. A series of dedicated experiments has been performed, to disentangle the effect of individu ...

In order to cope with the decarbonization challenge faced by many countries, fusion is one of the few alternatives to fossil fuels for the production of electricity. Two devices invented in the middle of the previous century have emerged as the most promis ...

An optimized plasma current ramp-down strategy is critical for safe and fast termination of plasma discharges in a tokamak demonstration fusion reactor (DEMO), both in planned and emergency scenarios, avoiding plasma disruptions and excessive heat loads to ...

This paper discusses the development of a benign termination scenario for runaway electron (RE) beams on ASDEX Upgrade and TCV. A systematic study revealed that a low electron density (n e) companion plasma was required to achieve a large MHD instability, ...

Rapid inter-discharge simulation and optimization using the RAPTOR code have allowed the development of a reliable and reproducible early heating strategy for an advanced tokamak (AT) scenario on ASDEX Upgrade. Solving for electron heat and current diffusi ...

Local gyrokinetic simulations are used to model turbulent transport for the first time in a representative high-performance plasma discharge projected for the new JT-60SA tokamak. The discharge features a double-null separatrix, 41 MW of combined neutral b ...

Electron-cyclotron waves are a tool commonly used in tokamaks, in particular to drive current. Their ability to drive current in a very localized manner renders them an optimal tool for MHD mode mitigation. However, such applications require high accuracy ...

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, ...

Reinforcement learning (RL) has shown promising results for real-time control systems, including the domain of plasma magnetic control. However, there are still significant drawbacks compared to traditional feedback control approaches for magnetic confinem ...

Carbon impurity transport is studied in the TCV tokamak using a charge exchange recombination diagnostic. TCVs flexible shaping capabilities were exploited to extend previous impurity transport studies to negative triangularity (delta < 0). A practical way ...

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 ...

Suprathermal electron studies in Tokamak plasmas by means of diagnostic measurements and modeling

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Design and implementation of a model-based hierarchical architecture for plasma shape control in the TCV tokamak

The quasi-continuous exhaust regime in ASDEX Upgrade and JET

Machine learning methods for locked-mode predictions in MAST-U plasmas

Real-time density profile simulations on ASDEX Upgrade and the impact of the edge boundary condition

Helicon normal modes in radially non-uniform plasma column

Turnstile flux as a measure for chaotic transport in magnetic confinement fusion devices

Investigating the influence of divertor baffles on nitrogen-seeded detachment in TCV with SOLPS-ITER simulations and TCV experiments

An upper pressure limit for low-Z benign termination of runaway electron beams in TCV

Experimental study and interpretative modelling of the Power Exhaust in Configurations with Multiple X-Points in TCV

Scenario optimization for the tokamak ramp-down phase in RAPTOR: A. Analysis and model validation on ASDEX Upgrade

Global fluid simulations of plasma turbulence in stellarators

Scenario optimization for the tokamak ramp-down phase in RAPTOR. Part B: safe termination of DEMO plasmas

Benign termination of runaway electron beams on ASDEX Upgrade and TCV

Inter-discharge optimization for fast, reliable access to ASDEX Upgrade advanced tokamak scenario

Gyrokinetic turbulence modeling of a high performance scenario in JT-60SA

Impact of microwave beam scattering by density fluctuations on the electron-cyclotron power deposition profile in tokamaks

Re-design of EU DEMO with a low aspect ratio

Towards practical reinforcement learning for tokamak magnetic control

Study of impurity C transport and plasma rotation in negative triangularity on the TCV tokamak

Divertor turbulence characterisation using Gas Puff Imaging in the TCV tokamak