Upgrade of the diagnostic neutral beam injector for the TCV tokamak

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

The neutral beam injection system is a key part of the TCV machine, which is actively exploited in different experimental campaigns. Development of a new ion-optical system (IOS) for the heating beam with intermediate particle energy (up to ~38 keV) has been performed, having obtained the beam simulation results by the IBSimu code. The validity of IBSimu calculations for the existing design concepts was cross-checked with the experimental data of beam profiles and divergence. The newly developed concept of

Suprathermal ions, i.e. ions with energies exceeding those of the bulk plasma, arise in diverse natural and laboratory plasmas ranging from the solar wind to magnetic confinement fusion (MCF) devices. In tokamaks, they are generated by external heating systems and fusion reactions, and a thorough characterization of their dynamics is crucial for safe operation. In tokamaks, the core plasma is separated from the walls by the last closed flux surface (LCFS), which exhibits a null point (X-point) in the poloid

In this work, we compare physics-based dynamic exhaust models with frequency response measurements (FRMs) of the global particle dynamics in the Tokamak à Configuration Variable (TCV). The aim is to understand and model the experimental in-vessel dynamic response of plasma and neutrals to deuterium gas puff modulations with three models of varying fidelity: a 0D three chamber model (TCM); DIV1D, which models the edge plasma in 1D, and SOLEDGE3X for 2D-axisymmetric modeling. We find that the dynamic behavior

The STEP prototype power plant (SPP) will utilize a double null diverted (DND) plasma topology to manage very high divertor heat fluxes within a compact design. The DND configuration provides advantages for divertor power balancing and H-mode access while it is connected, i.e.,

\delta R_{\text {sep}}

is small. Due to vertical instabilities and l

The comparison of simulations of plasma turbulence carried out with the GBS code, employing its latest multi-component plasma–neutral model, against a dedicated set of TCV discharges (TCV-X23) designed to investigate high-density divertor conditions characterised by strongly reduced target heat flux with respect to attached conditions, is presented. The TCV-X23 scenario, based on L-mode plasmas with a long outer divertor leg at low toroidal field, provides a well-diagnosed reference for boundary turbule

Machine learning algorithms are widely used to replace or accelerate highfidelity codes and to provide physical insight in complex problems. In this work, a random forest is applied to replace a 3D full-wave simulation performed using the COMSOL Multiphysics software. In our simulation, a microwave beam is propagating through a cylindrically shaped plasma and is scattered by it. The training data of the random forest consist of the electron density profiles and the corresponding distributions of the microwa

A Diagnostic Neutral Beam Injector (DNBI) is operated on the TCV Tokamak since 2000. Over the years, the plasma source and the ion optical system have benefited from several upgrades, whereas the power supply system remained almost unchanged. DNBI operation is now compromised by the obsolescence of both the power components and the control infrastructure. To allow for a long term reliable operation, a complete renew of the power supplies set is ongoing. It includes a high-speed current source rated 500 A/10

Negative triangularity (NT) plasmas achieve enhanced confinement without edge localized modes nor the need to exceed the L-H heating power threshold. Removing this H-mode accessibility constraint opens a new region of parameter space: scenarios with low external heating power. Using simple zero dimensional power balance and standard empirical scaling laws for confinement, we analyze the impact of external heating on several different reactor-relevant devices (i.e. SPARC, MANTA, ITER and DEMO). We determine

[Neo-classical] Tearing Modes ([N]TMs) control is crucial in high-energy devices like ITER due to the disruptions that may cause potential machine damage. This work presents a real-time [N]TM control strategy for the ITER Plasma Control System (PCS), aiming to predict [N]TMs present and their characteristics, and apply stabilization using Electron Cyclotron Heating (ECH). Key components of the [N]TM control scheme are a predictor with extended co-MRE solver, coupled mode width and frequency dynamics, and a

This paper describes the speaker diarization systems developed for the Second DIHARD Speech Diarization Challenge (DIHARD II) by the Speed team. Besides describing the system, which considerably outperformed the challenge baselines, we also focus on the lessons learned from numerous approaches that we tried for single and multi-channel systems. We present several components of our diarization system, including categorization of domains, speech enhancement, speech activity detection, speaker embeddings, clus

The electron cyclotron (EC) heating and current drive (H&CD) system developed for the ITER is made of 12 sets of high-voltage power supplies feeding 24 gyrotrons connected through 24 transmission lines (TL), to five launchers, four located in upper ports a ...

The understanding of the plasma dynamics in the scrape-off layer (SOL) of tokamaks is of crucial importance as we approach the ITER era. In this region, particles and heat coming from the core, through turbulent transport, flow along the magnetic field lines and are exhausted to the vessel. The processes taking place in the SOL govern the performance of the entire device, as they determine the impurity dynamics, the recycling level, the peak heat loads at the vessel, and have an important role in setting th

Negative triangularity tokamak plasmas are subject of an increased interest both in existing experiments and in studies of core physics as well as power handling relevant to the fusion demonstration power reactor. The ideal MHD stability calculations for the negative triangularity plasma extend the investigation of the TCV tokamak beta limits and edge stability to double null shapes, lower aspect ratio and negative shear. In case of the negative triangularity, the 2nd stability access is closed for ballooni

The TORoidal Plasma EXperiment (TORPEX) is a Simple Magnetized Torus (SMT) where open helical magnetic field lines are obtained from the superposition of a small vertical component on the main toroidal field. The SMT configuration features the main driving mechanisms of plasma instabilities characterising the Scrape-Off Layer (SOL) of larger tokamak devices, making TORPEX a very attractive machine to perform fusion oriented studies of plasma turbulence. A new experimental set-up has been recently developed

In the sheath region at the interface between plasmas and solid surfaces, quasi-neutrality and, in the case of magnetized plasmas, drift-ordering are violated. These two assumptions are typically made in plasma fluid models; the presence of a plasma-wall transition region, typical of all bounded systems, hampers therefore their use. This problem can be overcome by introducing a set of boundary conditions (BCs) for fluid models that properly describe the physics of the plasma-wall transition region. While th

The TORoidal Plasma EXperiment (TORPEX) is a basic plasma physics device where a Simple Magnetized Torus configuration (SMT) can be obtained superimposing a small vertical magnetic field component on the main toroidal field, resulting in open magnetic helical field lines. This configuration reproduces some of the main features of a tokamak plasma edge, including density and magnetic field gradient and curvature. In the last years, a complete study of electrostatic fluctuations and turbulence has been comple

To measure the transport of fast ions by various types of waves, complementary experiments are conducted in linear and toroidal magnetic fields in the large plasma device and the toroidal plasma experiment. Lithium sources that are immersed in the plasma p ...

In the foreseen upgrade of the Tokamak-a-Configuration-Variable (TCV) it is planned to add 3MW of additional RF power (3rd harmonic X-mode, X3, top-launch) to the present Electron Cyclotron (EC) system. With the upgrade of the EC-system, bringing the total EC power in X3-mode to 4.5MW, and the installation of 1 MW of neutral beam injection, a new avenue will be opened allowing the extensive study of H-mode physics in TCV. The envisaged new gyrotrons (lMW, 126GHz) are based on a minimum redesign of the 140 G

We investigate the redistribution of the neutral beam driven current in the presence of small scale turbulence in the ITER steady-state scenario. Gyrokinetic simulations show that anomalous transport of beam ions can be larger than collisional estimates. T ...

MAST plasmas with a safety factor above unity and a profile with either weakly reversed shear or broad low-shear regions, regularly exhibit long-lived saturated ideal magnetohydrodynamic (MHD) instabilities. The toroidal rotation is flattened in the presen ...

Upgrade of the diagnostic neutral beam injector for the TCV tokamak

Chat with Graph Search

Ion Optics With Oval Apertures for TCV NBI

Fast ion transport in complex magnetic field configurations in TORPEX

A multi-model system-identification comparison with the global particle dynamics in TCV

A Fast Double Null Control Concept Enabling Compact Fusion Reactors

Power exhaust and detachment with varying outer leg length using turbulence simulations and experiments designed for validation

A dual machine learning framework for the solution of the inverse scattering problem in cylindrical plasmas

High Voltage Modulator for the TCV Diagnostic Neutral Beam Injector

On the feasibility of Ohmically heated negative triangularity tokamak power plants

Progress on [N]TM modelling and control in the ITER Plasma Control System design

The Speed Submission to DIHARD II: Contributions & Lessons Learned

Status of the ITER Electron Cyclotron Heating and Current Drive System

Effects of plasma shaping on tokamak scrape-off layer turbulence

Stability limits for tokamak plasma with negative triangularity

Study of plasma fluctuations in new closed flux-surface configurations of the TORPEX experiment

The role of the sheath in magnetized plasma fluid turbulence

First results on the plasma fluctuations of the TORPEX device in the new magnetic field configurations

Measurements of interactions between waves and energetic ions in basic plasma experiments

Millimeter Wave System Upgrades On TCV: Additional X3 Power And Fast ECE Polarizers

Numerical modelling of electromagnetic turbulent transport of energetic ions in burning plasmas

Saturated ideal modes in advanced tokamak regimes in MAST