A5054868603- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Laser-Plasma Interactions and Diagnostics
- Nuclear reactor physics and engineering
- Ionosphere and magnetosphere dynamics
- Plasma Diagnostics and Applications
- Particle accelerators and beam dynamics
- Nuclear Materials and Properties
- Economic and Technological Developments in Russia
- Quality and Safety in Healthcare
- Cardiac Health and Mental Health
- Cardiac, Anesthesia and Surgical Outcomes
- Healthcare Systems and Public Health
- Power Line Communications and Noise
- Ion-surface interactions and analysis
- Semiconductor materials and devices
- High-Energy Particle Collisions Research
- Underwater Vehicles and Communication Systems
- Metal and Thin Film Mechanics
- Underwater Acoustics Research
- Gyrotron and Vacuum Electronics Research
- Atomic and Subatomic Physics Research
- Particle Accelerators and Free-Electron Lasers
- Traffic control and management
École Polytechnique Fédérale de Lausanne
2016-2025
General Atomics (United States)
2021-2024
Oak Ridge Associated Universities
2021-2024
University of California, San Diego
2019-2021
National Agency for New Technologies, Energy and Sustainable Economic Development
2021
Centro Cardiologico Monzino
2020
Max Planck Institute for Plasma Physics
2016
Divertor detachment is explored on the TCV tokamak in alternative magnetic geometries. Starting from typical single-null shapes, poloidal flux expansion at outer strikepoint varied by a factor of 10 to investigate X-divertor characteristics, and total 70 study properties super-X divertor. The effect an additional X-point near target investigated divertors. Detachment studied these plasmas during Ohmic density ramps with ion B drift away primary X-point. threshold, depth detachment, stability...
A detailed cross-device investigation on the role of filamentary dynamics in high-density regimes has been performed within EUROfusion framework, comparing ASDEX Upgrade (AUG) and TCV tokamaks. Both devices run density ramp experiments at different levels plasma current, keeping toroidal field or q95 constant order to disentangle parallel connection length current. During scan a field, both scrape-off layer (SOL) profiles tend develop clear SOL shoulder lower edge whenever current is...
Plasma exhaust has been identified as a major challenge towards the realisation of magnetic confinement fusion. To mitigate risk that single null divertor (SND) with high radiation fraction in scrape-of-layer (SOL) adopted for ITER will not extrapolate to DEMO reactor, EUROfusion consortium is assessing potential benefits and engineering challenges alternative configurations. Alternative configurations could be readily design include X (XD), Super-X (SXD), Snowflake (SFD) double (DND). The...
Most of the detachment experiments done to date on tokamak à configuration variable (TCV), both in standard and alternative divertor geometries, focused L-mode integrated core density ramps. In view extending these studies high-power, high-confinement regimes, where impurity seeding will be necessary for detachment, properties nitrogen seeded TCV are assessed here with extensive set edge diagnostics similarities differences () ramp elucidated. It is found that high current, reversed field...
Abstract The Tokamak à Configuration Variable (TCV) tokamak is in the midst of an upgrade to further its capability investigate conventional and alternative divertor configurations. To that end, modular removable gas baffles have been installed decrease coupling between plasma core. primarily seek suppress transit recycling neutrals closed flux surfaces. A first experimental campaign with has shown baffled remains compatible a wide range configurations including snowflake super- X divertors....
This paper investigates the power loads at inner and outer divertor targets of attached, Ohmic L-mode, deuterium plasmas in TCV tokamak, various experimental situations using an Infrared thermography system. The study comprises variations leg length target flux expansion, plasma current a reversal magnetic field direction. direct impact geometry on scrape-off layer (SOL) transport—parameterised by SOL fall-off , spreading factor Su in-out asymmetry—is reported for constant core properties....
Research towards a plasma exhaust solution for fusion power plant aims at validating edge physics models, strengthening predictive capabilities and improving the divertor configuration. The TCV tokamak is extensively used to investigate extent that geometric configuration modifications can affect performance. Recent experiments continue previous detachment studies of Ohmically heated L-mode plasmas in standard single-null configurations, benefitting from range improved diagnostic...
Within the EUROfusion MST1 work package, a series of experiments has been conducted on AUG and TCV devices to disentangle role plasma fueling shape for onset small ELM regimes. On both devices, regimes with high confinement are achieved if only two conditions fulfilled at same time. Firstly, density separatrix must be large enough (), leading pressure profile flattening separatrix, which stabilizes type-I ELMs. Secondly, magnetic configuration close double null (DN), reduction shear in...
A large database of reciprocating probe data from the edge plasma TCV (Tokamak à Configuration Variable) is used to test radial velocity scalings filaments analytical theory [Myra et al., Phys. Plasmas 13, 112502 (2006)]. The measured velocities are mainly scattered between zero and a maximum which varies as function size collisionality in agreement with scalings. scatter consistent mechanisms that tend slow individual filaments. While were clustered 0.5 2 km/s, minority reached outward high...
A deep understanding of plasma transport at the edge magnetically confined fusion plasmas is needed for handling and control heat loads on machine first wall. Experimental observations collected a number tokamaks over last three decades taught us that flux profiles divertor targets X-point configurations can be parametrized by using two scale lengths scrape-off layer (SOL) transport, separately characterizing main SOL () (Sq). In this work we challenge current interpretation these as well...
Abstract A set of experiments are planned to exploit the high SOL collisionality enabled by a tightly baffled slot divertor geometry suppress tungsten leakage in DIII-D. toroidal row graphite tiles from Small Angle Slot (SAS) is being coated with 10–15 μ m tungsten. New spectroscopic viewing chords in-vacuo optics will measure W gross erosion source surface spatial and temporal resolution. In parallel, bottom SAS changed flat ‘V’ shape. SOLPS-ITER/DIVIMP simulations conducted drifts using...
This paper reports on experimental observations TCV with a scan in upper triangularity , including negative triangularity, focusing the power fall-off length L-Mode. The is scanned from −0.28 to 0.47. Smaller measured at outer divertor target for decreasing together higher edge temperature leading increased confinement. effect observed both magnetic drift directions discharges deuterium and helium. In helium larger values are compared deuterium. inner has non-monotonic behaviour changing...
This paper explores the effects of particle drifts across magnetic field in TCV single-null plasmas using two-dimensional edge plasma transport code UEDGE. In particular, it aims to reproduce a double-peaked density target profile, feature which has been observed both at JET and forward-field ( drift core ions towards X-point) discharge. Initial simulations are performed with turned off. allows identification input parameters that strongly influence computed steady-state but not well known...
The small-angle slot (SAS) divertor of the DIII-D tokamak, and its upcoming upgrade, V-shape (SAS-V) divertor, are numerically investigated using SOLPS-ITER code package, including effect particle drifts, for a range plasma density, heating power, strike point position in slot, both magnetic field directions. simulations show that electron temperature near is reduced SAS-V compared to SAS, directions, such achieves detachment at lower value outboard mid-plane separatrix density. threshold...
The aim of this work is to provide an understanding detachment at TCV with emphasis on analysis the Balmer line emission. A new Divertor Spectroscopy System has been developed for purpose. Further development techniques allowed detailed information be extracted from three-body recombination contribution n=7 intensity. During density ramps, plasma target detaches as inferred a drop in ion current target. At same time $6\rightarrow2$ and $7\rightarrow2$ emission near dominated by...
The process of divertor detachment, whereby heat and particle fluxes to surfaces are strongly diminished, is required reduce loading erosion in a magnetic fusion reactor acceptable levels. In this paper the physics leading decrease total ion current (It), or 'roll-over', experimentally explored on TCV tokamak through characterization location, magnitude role various sinks sources including complete analysis power balance. These first measurements profiles ionisation hydrogenic radiation...
Abstract Recent experiments on Tokamak à Configuration Variable have made significant progress toward partial detachment of the outer divertor in neutral beam heated H-mode plasmas conventional and alternative configurations. The heating power required to enter was measured a range It is found that at core densities most favourable for access, L–H threshold largely independent poloidal flux expansion major radius divertor, snowflake minus configuration. A factor 2 reduction load achieved...
Abstract The beam properties of the BATMAN negative ion source, which is prototype one module source for ITER neutral injection system, are characterised by means three diagnostic techniques: emission spectroscopy (BES), experimental calorimeter mini-STRIKE and a copper calorimeter. main parameters—beam divergence, homogeneity top–bottom asymmetries—are studied in different operational scenarios: with magnetic filter field setups, settings gases (hydrogen or deuterium). Among all...
Abstract Obtaining acceptable conditions at the divertor targets of a next-step fusion experiment based on tokamak concept is expected to be particularly challenging because small predicted value plasma power exhaust channel width. An increased confidence in this prediction important forestall any issue and developing corresponding solutions. With present relying empirical scaling laws data from six tokamaks, letter tests these an additional device, TCV tokamak. Estimates width, λ q ,...
Abstract Impurity transport modeling of the new tungsten (W)-coated, V-shaped small angle slot (SAS) divertor in DIII-D tokamak was conducted using SOLPS-ITER plasma edge code package and DIVIMP impurity tracking code. The inboard baffle current SAS will be shifted closer to outboard baffle, creating a V-corner at vertex. In addition, coated with 10–15 μ m W for experiments studying high-Z sourcing leakage closed divertor. Modeling ‘SAS-VW’ predicts that these changes inner reduce gross...
In inboard-limited plasmas, foreseen to be used in future fusion reactors start-up and ramp down phases, the Scrape-Off Layer (SOL) exhibits two regions: "near" "far" SOL. The steep radial gradient of parallel heat flux associated with near SOL can result excessive thermal loads onto solid surfaces, damaging them and/or limiting operational space a reactor. this article, leveraging results presented [F. Nespoli et al., Nuclear Fusion 2017], we propose technique for mitigation suppression...
Abstract Experiments in DIII-D demonstrate that the upstream plasma density to detach an un-pumped slot divertor is similar for a V-shaped and flat-end slot, despite significantly higher neutral pressure contrast SOLPS-ITER predictions. The detachment threshold can be reduced by using in-slot instead of main-chamber gas fuelling or placing strike point on inner slanted baffle end, as described simulations with full drift physics. When increasing line-averaged (without extrinsic impurities),...
A simple analytic model for the repartition of Scrape-Off Layer (SOL) exhaust power between inner and outer divertors in a diverted low-density tokamak plasma is introduced. Electron heat conduction assumed to dominate transport, from outboard mid-plane divertor targets, with no sinks or sources SOL. Both channels are attached, high-recycling regime. The reasonable qualitative agreement recent TCV experimental data EMC3-Eirene simulations. For Single Null divertor, it reproduces...