A5058393712- Magnetic confinement fusion research
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Superconducting Materials and Applications
- Laser-Plasma Interactions and Diagnostics
- Plasma Diagnostics and Applications
- Solar and Space Plasma Dynamics
- Nuclear reactor physics and engineering
- Particle accelerators and beam dynamics
- Nuclear Materials and Properties
- Atomic and Subatomic Physics Research
- Laser-induced spectroscopy and plasma
- Dust and Plasma Wave Phenomena
- Fluid Dynamics and Turbulent Flows
- Atomic and Molecular Physics
- Metal and Thin Film Mechanics
- Generative Adversarial Networks and Image Synthesis
- Nuclear Physics and Applications
- Advanced Data Storage Technologies
- Magnetic Field Sensors Techniques
- Geophysics and Sensor Technology
- High-pressure geophysics and materials
- Plasma and Flow Control in Aerodynamics
- Advanced Control Systems Optimization
- Vehicle Dynamics and Control Systems
École Polytechnique Fédérale de Lausanne
2016-2025
Plasma Technology (United States)
2013-2023
Fusion Academy
2013-2023
Fusion (United States)
2013-2023
Max Planck Institute for Plasma Physics
2023
ITER
2019
CEA Cadarache
2018
Massachusetts Institute of Technology
2013-2016
Princeton Plasma Physics Laboratory
2014-2016
University of California, San Diego
2016
Based on the drift-reduced Braginskii equations, Global Solver, GBS, is able to model scrape-off layer (SOL) plasma turbulence in terms of interplay between outflow from tokamak core, turbulent transport, and losses at vessel. Model GBS numerical algorithm, simulation results are described. has been first developed basic physics devices, such as linear simple magnetized toroidal which contain some main elements SOL a simplified setting. In this paper we summarize findings obtained carried...
The mechanism for blob generation in a toroidal magnetized plasma is investigated using time-resolved measurements of two-dimensional structures electron density, temperature, and potential. blobs are observed to form from radially elongated structure that sheared off by the $\mathbf{E}\ifmmode\times\else\texttimes\fi{}\mathbf{B}$ flow. generated an interchange wave increases amplitude extends response decrease radial pressure scale length. dependence upon length discussed.
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...
The object of this review is to summarize the achievements research on Alcator C-Mod tokamak [Hutchinson et al., Phys. Plasmas 1, 1511 (1994) and Marmar, Fusion Sci. Technol. 51, 261 (2007)] place that in context quest for practical fusion energy. a compact, high-field tokamak, whose unique design operating parameters have produced wealth new important results since it began operation 1993, contributing data extends tests critical physical models into parameter ranges regimes. Using only...
Self-consistent full-size turbulent-transport simulations of the divertor and SOL existing tokamaks have recently become feasible. This enables direct comparison turbulence against experimental measurements. In this work, we perform a series diverted Ohmic L-mode discharges on TCV tokamak, building first-of-a-kind dataset for validation edge models. dataset, referred to as TCV-X21, contains measurements from 5 diagnostic systems -- giving total 45 1- 2-D observables in two toroidal magnetic...
The radial propagation of blobs generated from plasma instabilities is investigated in an open magnetic field line configuration. Blob cross-field velocities and sizes are obtained internal probe measurements using pattern recognition. By varying the ion mass, normalized vertical blob scale a[over] scanned < 1 to > 1. An analytical expression for velocity including polarization currents, parallel currents sheath, ion-neutral collisions derived shows good quantitative agreement with...
Velocity fields and density fluctuations of edge turbulence are studied in I-mode [F. Ryter et al., Plasma Phys. Controlled Fusion 40, 725 (1998)] plasmas the Alcator C-Mod [I. H. Hutchinson Plasmas 1, 1511 (1994)] tokamak, which characterized by a strong thermal transport barrier while providing little or no to both bulk impurity particles. Although previous work showed clear geodesic-acoustic modes (GAM) on C-Mod, using newly implemented, gas-puff-imaging based time-delay-estimate velocity...
The MIT Plasma Science and Fusion Center collaborators are proposing a high-performance Advanced Divertor RF tokamak eXperiment (ADX)-a specifically designed to address critical gaps in the world fusion research programme on pathway next-step devices: nuclear science facility (FNSF), pilot plant (FPP) and/or demonstration power (DEMO). This high-field (>= 6.5 T, 1.5 MA), high density (P/S similar MW m(-2)) will test innovative divertor ideas, including an 'X-point target divertor' concept,...
With fusion device performance hinging on the edge pedestal pressure, it is imperative to experimentally understand physical mechanism dictating characteristics and validate improve predictive models. This Letter reports direct evidence of density magnetic fluctuations showing stiff onset an instability leading saturation Alcator C-Mod tokamak. Edge stability analyses indicate that unstable both ballooning mode kinetic in agreement with observations.
Abstract This paper describes joint ITPA studies of the I-mode regime, which features an edge thermal barrier together with L-mode-like particle and impurity transport no localized modes (ELMs). The regime has been demonstrated on Alcator C-Mod, ASDEX Upgrade DIII-D tokamaks, over a wide range device parameters pedestal conditions. Dimensionless at show overlap across devices extend to low collisionality. When they are matched, temperature profiles also similar. Pedestals stable...
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...
This paper presents the current wall-embedded Langmuir probe system installed on Tokamak à Configuration Variable (TCV), as well analysis tool chain used to interpret current-voltage characteristic obtained when probes are operated in swept-bias conditions. The is based a four-parameter fit combined with minimum temperature approach. In order reduce effect of plasma fluctuations and measurement noise, several characteristics usually averaged before proceeding fitting. impact this procedure...
Abstract In magnetic confinement thermonuclear fusion the exhaust of heat and particles from core remains a major challenge. Heat leaving are transported via open field lines to region reactor wall, called divertor. Unabated, particle fluxes may become intolerable damage Controlled ‘plasma detachment’, regime characterized by both large reduction in plasma pressure temperature at divertor target, is required reduce onto Here we report systematic approach towards achieving this critical need...
Future fusion reactors require a safe, steady-state divertor operation. With deep detachment, which is typically induced by impurity seeding, the radiation concentrates in small region at X-point or on closed flux surfaces above X-point. This so-called radiator (XPR) moves further inside confined with increasing seeding and location can be actively controlled. At AUG, parameter space for operation an XPR was significantly extended, using active feedback location. The observed nearly whole...
Abstract The impact of plasma shaping on the properties high density H-mode scrape-off layer (SOL) profiles and transport at outer midplane has been investigated Tokamakà configuration variable. experimental dataset acquired by evolving upper triangularity while keeping other parameters constant. scan comprises <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mi>δ</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">u</mml:mi>...
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...
The effect of the upcoming TCV divertor upgrade on distribution neutrals and onset detachment is studied using 2D transport code simulations. centered around installation a gas baffle to form chamber variable closure. SOLPS-ITER simulations predict that geometry selected be installed in 2019 increases neutral density by factor ∼5 compression one order magnitude typical single null, Ohmic heated scenarios (330 kW). further with addition auxiliary heating systems (1.2 MW). Simulations show...
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 shows experimental results from the TCV tokamak that indicate plasma-molecule interactions involving $D_2^+$ and possibly $D^-$ play an important role as sinks of energy (through hydrogenic radiation well dissociation) particles during divertor detachment if low target temperatures ($< 3$ eV) are achieved. Both molecular activated recombination (MAR) ion source reduction due to a power limitation effect shown be in reducing flux density ramp. In contrast, electron-ion (EIR) sink...
Abstract In recent years, negative triangularity (NT) has emerged as a potential high-confinement L-mode reactor solution. this work, detachment is investigated using core density ramps in lower single null Ohmic plasmas across wide range of upper, lower, and average (the mean upper triangularity: δ ) the TCV tokamak. It universally found that more difficult to access for NT shaping. The outer divertor leg discharges with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"...
Abstract Plasma edge simulations with the SOLPS-ITER code are performed to study influence of divertor baffles on nitrogen-seeded detachment in TCV single-null, L-mode discharges. Scans nitrogen seeding rate conducted both baffled and unbaffled divertors, where is found yield lower target temperatures heat fluxes than baffles-only seeding-only. The cumulative effects parameters explained by two-point model. neutral density compression increase baffles, due main chamber conductance, as a...
Abstract 2D profiles of electron density and neutral temperature are inferred from multi-delay Coherence Imaging Spectroscopy data divertor plasmas using a non-linear inversion technique. The inference is based on imaging the spectral line-broadening Balmer lines can differentiate between Doppler Stark broadening components by measuring fringe contrast at multiple interferometric delays simultaneously. model has been applied to images generated simulated evaluate its performance. Typical...
The mechanism for blob generation is detailed in the toroidal magnetized plasma of TORPEX device [Fasoli et al., Phys. Plasmas 13, 055902 (2006)] using an experimental configuration, which features a region dominated by coherent wave and on low field side characterized propagation blobs. Predictions from linearized 2D drift-reduced Braginskii equations are compared with data, revealing interchange nature wave. dynamics formation investigated time-resolved measurements two-dimensional...
A methodology for plasma turbulence code validation is discussed, focusing on quantitative assessment of the agreement between experiments and simulations. The present work extends analysis carried out in a previous paper [P. Ricci et al., Phys. Plasmas 16, 055703 (2009)] where observables were introduced. Here, it discussed how to quantify simulations with respect each observable, define metric evaluate this globally, and—finally—how assess quality procedure. then applied simulation basic...