A5086537647- Magnetic confinement fusion research
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Gas Dynamics and Kinetic Theory
- Superconducting Materials and Applications
- Laser-Plasma Interactions and Diagnostics
- Plasma Diagnostics and Applications
- Particle accelerators and beam dynamics
- Computational Fluid Dynamics and Aerodynamics
- Rocket and propulsion systems research
- Nuclear reactor physics and engineering
- Laser-induced spectroscopy and plasma
- Radiative Heat Transfer Studies
- Fluid Dynamics and Turbulent Flows
- Plasma and Flow Control in Aerodynamics
- Atomic and Subatomic Physics Research
- Calibration and Measurement Techniques
- Laser Design and Applications
- Electrostatic Discharge in Electronics
- Combustion and flame dynamics
- Vacuum and Plasma Arcs
- X-ray Spectroscopy and Fluorescence Analysis
- Pulsed Power Technology Applications
- Atmospheric Ozone and Climate
- Aerodynamics and Fluid Dynamics Research
École Polytechnique Fédérale de Lausanne
2016-2025
Institut de Recherche sur la Fusion par Confinement Magnétique
2024
CEA Cadarache
2024
Max Planck Institute for Plasma Physics
2016-2024
Fusion (United States)
2019
Fusion Academy
2019
The University of Queensland
2011-2017
Max Planck Society
2016
Laboratoire d'Énergétique Moléculaire et Macroscopique, Combustion
2014
École Centrale d'Électronique
2013
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...
Abstract 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 low density ( n e ) companion plasma was required to achieve large MHD instability, which expelled confined REs over wetted area allowed conversion magnetic energy radiation. Control achieved via neutral pressure regulation agnostic material injection method. The recombination found be dependent impurity species, quantity RE...
Hypersonic testing in impulse facilities replicates various flow characteristics accurately; however, because of the short test times, some phenomena cannot be fully simulated. Previous has been conducted with preheated walls up to 800 K; this falls well typical temperatures characteristic ablators hypervelocity reentry (~2000–3000 K). The concept presented here is use resistive heating on a carbon–carbon model preheat immediately before conducting test. This method enabled at wall excess...
Key plasma physics and real-time control elements needed for robustly stable operation of high fusion power discharges in ITER have been demonstrated recent research worldwide.Recent analysis has identified the current density profile as main drive disruptive instabilities simulating ITER's baseline scenario with low external torque.Ongoing development model-based active magnetohydrodynamic is improving stability multiple scenarios.Significant advances made toward physicsbased prediction...
Abstract The favorable confinement properties of negative-triangularity (NT) tokamak configurations were discovered in the TCV late 1990s and documented over two following decades, through investigations predominantly electron-heated plasmas limited topologies. most recent experimental campaign has marked a leap forward, characterized by development variety diverted NT shapes that are robustly stable with basic Ohmic heating. application auxiliary heating, directed now at both electrons ions...
Abstract A series of experiments have been executed at JET to assess the efficacy newly installed shattered pellet injection (SPI) system in mitigating effects disruptions. Issues, important for ITER disruption mitigation system, such as thermal load mitigation, avoidance runaway electron (RE) formation, radiation asymmetries during quench electromagnetic control and RE energy dissipation addressed over a large parameter range. The efficiency has examined various SPI strategies. paper...
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>...
2019) 076038 (17pp) (mainly ETG and ITG) by 50%.This suggests that, in these plasmas, the increase turbulent transport due to outward shift of density might play an important role decrease pedestal performance.
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....
Abstract Precise values for radiated energy in tokamak disruption experiments are needed to validate mitigation techniques burning plasma tokamaks like ITER and SPARC. Control room analysis of power ( P rad ) on JET assumes axisymmetry, since fitting 3D radiation structures with limited bolometry coverage is an under-determined problem. In mitigated disruptions, toroidally asymmetric 3D, due fast-growing MHD modes localized impurity sources. To address this problem, Emis3D adopts a physics...
Abstract The pre-thermal quench (pre-TQ) dynamics of a pure deuterium ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi mathvariant="normal">D</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:math> ) shattered pellet injection (SPI) into <mml:mn>3</mml:mn> <mml:mstyle scriptlevel="0"/> <mml:mi>MA</mml:mi> / <mml:mn>7</mml:mn> <mml:mi>MJ</mml:mi> JET H-mode plasma is studied via 3D non-linear MHD modelling with the JOREK code....
Abstract Plasma disruptions present a significant challenge to the viability of fusion energy production in tokamak reactors. Among disruption mitigation techniques, shattered pellet injection (SPI) has emerged as promising approach. The results presented this paper show novel findings impact nitrogen and neon seeding on sequence following SPI Joint European Torus (JET). This study exposes an order magnitude reduction pre-thermal quench duration for highly seeded plasmas pure deuterium SPI,...
Abstract We present a model for the particle balance in post-disruption runaway electron plateau phase of tokamak discharge. The is constructed with help of, and applied to, experimental data from TCV discharges investigating so-called ``low-Z benign termination'' mitigation scheme. In termination scheme, free density first reduced order subsequently induced MHD instability to grow rapidly spread electrons widely across wall. show that observed non-monotonic dependence measured neutral...
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...
Divertor detachment in the TCV tokamak has been investigated through experiments and modelling. Density ramp were carried out ohmic heated L-mode pulses with ion ∇B drift directed away from primary X-point, similar to previous studies [1]. Before roll-over current outer strike point, C III Dα emission leg recede slowly point toward at a rate of ∼2.0 × 10−19 m/m−3 along magnetic field as electron temperature reduces increasing density. Around onset detachment, upstream density profile target...
The Tokamak à Configuration Variable (TCV) has recently been equipped with gas baffles to increase its divertor closure for a broad range of magnetic geometries. First experimental results reported in Reimerdes et al. (2021) demonstrated compatibility geometries and confirmed the main design constraints baffles, particular an increased neutral pressure. present article presents more in-depths analysis extended experiments this first baffle assessment on TCV boundary plasma. It is shown that...
Experiments were conducted using the X2 expansion tube at two conditions representative of flight velocities 10.0 and for a vehicle entry into Earth's atmosphere. Calibrated spectral measurements made radiating shock layers across through surface model. These provided unique dataset validation computational codes used in calculation incident vacuum ultraviolet radiative heat flux. Computational simulations equilibrium gas chemistry Specair program showed good agreement with measurements.
Abstract Disruption mitigation remains a critical, unresolved challenge for ITER. To aid in addressing this challenge, shattered pellet injection (SPI) system was installed on JET and experiments conducted at range of thermal energy fractions stored energies excess 7 MJ. The primary goals these were to investigate the efficacy SPI ability plasma assimilate multiple pellets. Single injections produced saturation total radiated ( W rad ) with increasing injected neon content, suggesting...
Abstract Nonlinear 3D MHD simulations of shattered-pellet injection (SPI) in JET show prototypical SPI-driven disruptions using the M3D-C1 and NIMROD extended-MHD codes. Initially, radiation-driven thermal quenches are accelerated by activity as pellet crosses rational surfaces, leading to a radiation spike, global stochasticization magnetic field, complete quench. Eventually, current quenches, preceded spike seen Ohmic heating becomes equal radiative cooling. The results qualitatively...
The Swiss Plasma Center (SPC) is planning a divertor upgrade for the TCV tokamak. aims at extending research of conventional and alternative configurations to operational scenarios regimes greater relevance fusion reactor. main elements are installation an in-vessel structure form chamber variable closure enhanced diagnostic capabilities, increase pumping capability addition new poloidal field coils. project follows staged approach carried out in parallel with heating system. First...
This correction pertains to minor elements that were in error the original article when it was first published online [https://doi.org/10.2514/1.J056021]. On page, third author’s middle initial incorrect. The correct full name is Steven W. Lewis.