A5061252280- Magnetic confinement fusion research
- Fusion materials and technologies
- Superconducting Materials and Applications
- Laser-Plasma Interactions and Diagnostics
- Nuclear Physics and Applications
- Ionosphere and magnetosphere dynamics
- Particle accelerators and beam dynamics
- Nuclear reactor physics and engineering
- Particle Detector Development and Performance
- Advanced X-ray and CT Imaging
- Plasma Diagnostics and Applications
- Radiation Detection and Scintillator Technologies
- Medical Imaging Techniques and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Atomic and Molecular Physics
- Solar and Space Plasma Dynamics
- Advanced Data Storage Technologies
- Atomic and Subatomic Physics Research
- Advanced X-ray Imaging Techniques
- Geophysical and Geoelectrical Methods
- Cold Fusion and Nuclear Reactions
- Electrostatic Discharge in Electronics
- Geomagnetism and Paleomagnetism Studies
- Gyrotron and Vacuum Electronics Research
- Silicon Carbide Semiconductor Technologies
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2015-2024
CEA Cadarache
2015-2024
Institut de Recherche sur la Fusion par Confinement Magnétique
2009-2024
Southwestern Institute of Physics
2011-2020
Southwest Jiaotong University
2020
Royal Military Academy
2020
Institute of Plasma Physics
2019
Warsaw University of Technology
2018
Institute for Plasma Research
2011-2017
Japan External Trade Organization
2015
Significant progress has been made in the area of advanced modes operation that are candidates for achieving steady state conditions a fusion reactor. The corresponding parameters, domain operation, scenarios and integration issues discussed this chapter. A review presently developed scenarios, including discussions on operational space, is given. heating current drive recent years, especially off-axis drive, which essential achievement required profile. actuators necessary to produce...
The plasma diagnostic and control (D&C) system for a future tokamak demonstration fusion reactor (DEMO) will have to provide reliable operation near technical physics limits, while its front-end components be subject strong adverse effects within the nuclear high temperature environment. ongoing developments ITER D&C represent an important starting point progressing towards DEMO. Requirements detailed exploration of are however pushing design using sophisticated methods aiming large spatial...
Simultaneous current ramping and application of lower hybrid heating drive (LHCD) have produced a region with zero density within measurement errors in the core ( r/a< or =0.2) JET tokamak optimized shear discharges. The reduction is consistent simple physical explanation numerical simulations radial diffusion including effects LHCD. However, clamped at zero, indicating existence mechanism which prevents it from becoming negative.
This paper proposes a control-oriented approach to the tokamak plasma current profile dynamics. It is established based on consistent set of simplified relationships, in particular for microwave drive sources, rather than exact physical modelling. Assuming that proper model advanced control schemes can be using so-called cylindrical approximation and neglecting diamagnetic effects, we propose focuses flux diffusion (from which inferred). Its inputs are some real-time measurements available...
Abstract Since the last IAEA Fusion Energy Conference in 2018, significant progress of experimental program HL-2A has been achieved on developing advanced plasma physics, edge localized mode (ELM) control physics and technology. Optimization confinement performed. In particular, high- β N H-mode plasmas exhibiting an internal transport barrier have obtained (normalized pressure reached up to 3). Injection impurity improved confinement. ELM using resonance magnetic perturbation or injection a...
An initial concept for the plasma diagnostic and control (D&C) system has been developed as part of European studies towards development a demonstration tokamak fusion reactor (DEMO). The main objective is to develop feasible, integrated design DEMO D&C that can provide reliable high performance (electricity output) over extended periods operation. While power maximized when operating near operational limits tokamak, reliability operation typically improves choosing parameters significantly...
Abstract Diagnostics play a pivotal role in nuclear fusion experimental reactors, supporting physical studies, modelling, and plasma control. However, most diagnostics provide limited partial information about the plasma's status. For instance, magnetic probes measure only external fields, while interferometers, polarimeters, bolometers deliver line-integrated measurements, necessitating specific inversion algorithms to extract local information. In case of bolometers, tomographic inversions...
Scenarios of steady-state, fully non-inductive current in Tore Supra are predicted using a package simulation codes (CRONOS). The plasma equilibrium and transport consistently calculated with the deposition power. achievement high injected energy discharges up to 1 GJ is shown. Two main scenarios considered: low density regime 90% driven by lower hybrid waves—lower drive (LHCD)—and combining LHCD ion cyclotron resonance heating bootstrap fraction 25%. predictive simulations existing also reported.
By incorporating parametric instabilities of lower hybrid (LH) waves into a ray-tracing Fokker-Planck code, accurate simulations the LH deposition profiles are provided, which useful for interpreting long-lasting internal transport barriers (ITBs) sustained by current drive (LHCD) on JET (Joint European Torus). Utilizing new model, simulation $q$-profile evolution results in agreement with that provided motional Stark effect reconstructed equilibria. Low magnetic shear...
Results from an extensive database analysis of JET density profiles in stationary conditions show that the peaking factor ne0/⟨ne⟩ H modes increases near 1.2 at high collisionality to around 1.5 as plasma decreases towards values expected for ITER. This result confirms earlier observation on AUG. The behaviour L is remarkably different modes, scaling with overall shear (ne0/⟨ne⟩ ∼ 1.5li), independently collisionality. H-mode no dependence, except lowest collisionalities. No evidence LTe,...
Real-time simultaneous control of several radially distributed magnetic and kinetic plasma parameters is being investigated on JET, in view developing integrated advanced tokamak scenarios. This paper describes the new model-based profile controller which has been implemented during 2006–2007 experimental campaigns. The aims to use combination heating current drive (H&CD) systems—and optionally poloidal field (PF) system—in an optimal way regulate evolution parameter profiles such as...
Optimized shear (OS) experiments in JET can generate an internal transport barrier (ITB) during a high power heating phase early the plasma discharge. A strong link is generally observed between formation of and location integer q magnetic surface within low (s = r/q(dq/dr)) region plasma. However, if q-profile for such modified by applying lower hybrid current drive (LHCD) before main pulse, to provide reduced or negative core, ITBs be formed which does not exhibit any apparent association...
Internal transport barriers (ITBs) can be produced in JET by the application of strong additional heating during current rise phase plasma discharge. Using up to 3 MW lower hybrid power tailor q-profile prior main phase, a large variety q-profiles ranging from low positive negative central shear have been obtained (0.4 MA s−1). With magnetic s = (r/q)(dr/dq), analysis ITB triggering reveals correlation between formation and q min reaching an integer value (q 2 or 3). This observation is...
Quasi-steady operation has been achieved at JET in the high-confinement regime with internal transport barriers (ITBs). The ITB maintained up to 11 s. This duration, much larger than energy confinement time, is already approaching a current resistive time. high-performance phase limited only by plant constraints. radial profiles of thermal electron and ion pressures have steep gradients typically mid-plasma radius. A large fraction non-inductive (above 80%) sustained throughout poloidal beta...
Quasistationary operation has been achieved on the Joint European Torus tokamak in internal-transport-barrier (ITB) scenarios, with discharge time limited only by plant constraints. Full current drive was obtained over all high performance phase using lower hybrid drive. For first feedback control total pressure and electron temperature profile implemented using, respectively, neutral beams ion-cyclotron waves. Although impurity accumulation could be a problem steady state ITBs, these...
In order to simultaneously control the current and pressure profiles in high performance tokamak plasmas with internal transport barriers (ITB), a multi-variable model-based technique has been proposed. New algorithms using truncated singular value decomposition (TSVD) of linearized model operator retaining distributed nature system have implemented JET system. Their simplest versions applied density profile reversed shear three heating drive actuators (neutral beam injection, ion cyclotron...
This paper describes a new technique which has been implemented on the JET tokamak to investigate integrated real-time control of several plasma profiles simultaneously (such as current, temperature and pressure) reports results first experimental tests. The are handled through their projection suitable basis functions according Galerkin scheme. Their response three actuators (heating current drive powers injected in plasma) is linearized an experimentally deduced multi-input multi-output...
A new ITER-relevant lower hybrid current drive (LHCD) launcher, based on the passive-active-multijunction (PAM) concept, was brought into operation Tore Supra tokamak in autumn 2009. The PAM launcher concept designed view of ITER to allow efficient cooling waveguides, as required for long pulse operation. In addition, it offers low power reflection close cut-off density, which is very attractive ITER, where large distance between plasma and wall may bring density front values. first...
The mission of HL-2A is to explore the key physical topics relevant ITER and advanced tokamak operation (e.g. future HL-2M), such as access H-mode, energetic particle physics, edge-localized mode (ELM) mitigation/suppression disruption mitigation. Since 2016 Fusion Energy Conference, team has focused on investigations following areas: (i) pedestal dynamics L–H transition, (ii) techniques ELM control, (iii) turbulence transport, (iv) physics. results demonstrated that increase mean shear flow...
In JET, advanced tokamak research mainly focuses on plasmas with internal transport barriers (ITBs) that are strongly influenced by the current density profile. A previously developed optimized shear regime low magnetic in plasma centre has been extended to deeply negative configurations. High fusion performance wide ITBs obtained transiently central configuration: HIPB98(y,2) ∼ 1.9, βN = 2.4 at Ip 2.5 MA. At somewhat reduced performance, electron and ion have sustained full drive operation...
An integrated plasma profile control strategy, ARTAEMIS , is being developed for extrapolating present-day advanced tokamak (AT) scenarios to steady-state operation. The approach based on semi-empirical modelling and was initially explored JET (Moreau et al 2008 Nucl. Fusion 48 106001 ). This paper deals with the general applicability of this strategy simultaneous magnetic kinetic various tokamaks. determination device-specific, control-oriented models that are needed compute optimal...
Extensive experimental data support reliable power deposition and current drive by lower-hybrid (LH) waves in conditions where a large spectral gap exists between the nominal parallel index of refraction prescribed antenna characteristics phasing, that required for significant Landau damping to take place. We argue only modification initial spectrum at plasma edge could explain observations. Based on this assumption, new prescription simulations LH using ray-tracing Fokker-Planck modelling...
This paper is focused on the soft x-ray (SXR) tomography system setup at Tore Supra (DTOMOX) and recent developments made to automatically get precise information about plasma features from inverted data. The first part describes main aspects of tomographic inversion optimization process. Several observations are using this new tool a set shape factors defined help characterizing emissivity field in real-time perspective. second presents detailed off-line analysis comparing positions...