A. Ekedahl
A5043027638- Magnetic confinement fusion research
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Fusion materials and technologies
- Ionosphere and magnetosphere dynamics
- Laser-Plasma Interactions and Diagnostics
- Plasma Diagnostics and Applications
- Gyrotron and Vacuum Electronics Research
- Nuclear reactor physics and engineering
- Nuclear Materials and Properties
- Solar and Space Plasma Dynamics
- Electromagnetic Launch and Propulsion Technology
- Laser-induced spectroscopy and plasma
- Nuclear Physics and Applications
- High-Energy Particle Collisions Research
- Quantum chaos and dynamical systems
- Spacecraft and Cryogenic Technologies
- Dust and Plasma Wave Phenomena
- Antenna Design and Analysis
- Acoustic Wave Resonator Technologies
- Electrostatic Discharge in Electronics
- Physics of Superconductivity and Magnetism
- Tropical and Extratropical Cyclones Research
- Pulsed Power Technology Applications
- Laser Design and Applications
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2015-2024
Institut de Recherche sur la Fusion par Confinement Magnétique
2008-2024
CEA Cadarache
2015-2024
Southwestern Institute of Physics
2011-2020
Southwest Jiaotong University
2020
Royal Military Academy
2020
American University of Beirut
2017
Tsinghua University
2017
Japan External Trade Organization
2015
Chalmers University of Technology
1997-2014
The EAST research program aims to demonstrate steady-state long-pulse advanced high-performance H-mode operations with ITER-like poloidal configuration and RF-dominated heating schemes. Since the 2014 IAEA FEC, has been upgraded all ITER-relevant auxiliary current drive systems, enabling investigation of plasma profile control by coupling/integration various combinations. Fully non-inductive (H 98,y2 > 1.1) was extended over 60 s for first time sole RF plus good power coupling impurity...
Since the last IAEA-FEC in 2016, EAST physics experiments have been developed further support of high-performance steady-state operation for ITER and CFETR.First demonstration >100 seconds time scale long-pulse scenario with a good plasma performance (H98(y2) ~ 1.1) control impurity heat exhaust upper tungsten divertor has achieved on using pure radio frequency (RF) power heating current drive.The operational domain significantly extended towards more CFETR related high beta regime (βP ~2.5...
With WEST (Tungsten Environment in Steady State Tokamak) (Bucalossi et al 2014 Fusion Eng. Des. 89 907–12), the Tore Supra facility and team expertise (Dumont Plasma Phys. Control. 56 075020) is used to pave way towards ITER divertor procurement operation. It consists implementing a configuration installing ITER-like actively cooled tungsten monoblocks tokamak, taking full benefit of its unique long-pulse capability. user platform, open all partners. This paper describes physics basis WEST:...
A 20 MW/5 GHz lower hybrid current drive (LHCD) system was initially due to be commissioned and used for the second mission of ITER, i.e. Q = 5 steady state target. Though not part currently planned procurement phase, it is now under consideration an earlier delivery. In this paper, both physics technology conceptual designs are reviewed. Furthermore, appropriate work plan also developed. This design, R&D, installation a MW LHCD on ITER follows Scientific Technical Advisory Committee...
The Advanced LOwer Hybrid Antenna (ALOHA) code, has been developed to improve the modelling of coupling lower hybrid (LH) waves from antenna a cold inhomogeneous plasma while keeping fast tool. In contrast previous code Slow Wave ANtenna (SWAN) (that only described interaction slow wave between waveguides and in 1D model), equations are now solved 2D including contribution both waves, with low computational cost. This approach is completed either by full-wave computation that takes into...
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...
The observation of internal transport barriers (ITBs) in which ion thermal diffusivity is reduced to a neoclassical level has been made for the first time tokamak plasmas fueled with deuterium and tritium ions using broad current density profile. heating profiles required obtain an ITB are similar D-T D-D plasmas. Central temperatures 40 keV plasma pressure gradients ${10}^{6}\mathrm{Pa}/\mathrm{m}$ were observed plasma, leading fusion triple product...
In JET, lower hybrid (LH) and ion cyclotron resonance frequency (ICRF) wave absorption in the scrape-off layer can lead to enhanced heat fluxes on some plasma facing components (PFCs). Experiments have been carried out characterize these loads order to: (i) prepare JET operation with Be wall which has a reduced power handling capability as compared carbon (ii) better understand physics driving phenomena propose solutions for next generation systems reduce them. When using ICRF, hot spots are...
A detailed study of lower hybrid current drive (LHCD) in ITER is provided, focusing on the wave propagation and mechanisms. combination ray-tracing Fokker–Planck calculations are presented for various plasma scenarios, frequency polarization. The dependence driven location power deposition upon coupled spectrum systematically determined, order to set objectives antenna design. respective effects finite-power levels, magnetic trapping, spectra accounted quantitatively estimated. sensitivity...
A 4.6 GHz lower-hybrid current drive (LHCD) system has been firstly commissioned in EAST the 2014 campaign. The first LHCD results with show that LHW can be coupled to plasma a low reflection coefficient, and rotation, modify profile, heat effectively. By means of configuration optimization local gas puffing near antenna, good LHW–plasma coupling coefficient less than 5% is obtained. maximum power up 3.5 MW. (CD) efficiency 1.1 × 1019 m−2 W−1 central electron temperature above 4 keV,...
Abstract ITER will operate with a tungsten divertor, material featuring surface morphology changes when exposed to helium plasmas, in particular the formation of so called fuzz under specific conditions. Investigating interactions between plasma facing components and plasmas tokamak environment is therefore key point consolidate predictions for divertor performance lifetime. To this end, dedicated campaign was performed full WEST tokamak, cumulating ∼2000 s repetitive L mode discharges. It...
Abstract The full W environment that is now foreseen for ITER puts strong emphasis on experimental results obtained in present devices similar conditions. In this context, the WEST tokamak well equipped to bring key contributions preparation of operation, thanks its capability perform long pulses dominant electron heating, torque-free scheme based RF systems, and ITERgrade actively cooled divertor. Recent interest cover understanding tungsten contamination evaluation conditioning methods,...
Fuel retention, a crucial issue for next step devices, is assessed in present-day tokamaks using two methods: particle balance performed during shots and post-mortem analysis carried out shutdowns between experimental campaigns. Post-mortem generally gives lower estimates of fuel retention than integrated balance. In order to understand the discrepancy these methods, dedicated campaign has been Tore Supra load vessel walls with deuterium (D) monitor trapped D inventory through The was...
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...
Aimed at high-confinement (H-mode) plasmas in the Experimental Advanced Superconducting Tokamak (EAST), effect of local gas puffing from electron and ion sides a lower hybrid wave (LHW) antenna on LHW–plasma coupling high-density experiments with current drive (LHCD) are investigated EAST. results show that side is more favourable to improve compared side. Investigations indicate without affected by density near LHW grill (grill density), hence leading multi-transition low–high–low (L–H–L)...
First principle modeling of the lower hybrid (LH) current drive in tokamak plasmas is a longstanding activity, which gradually gaining accuracy thanks to quantitative comparisons with experimental observations. The ability reproduce simulatenously plasma and non-thermal bremsstrahlung radial profiles hard x-ray (HXR) photon energy range represents this context significant achievement. Though subject limitations, ray tracing calculations are commonly used for describing wave propagation...
EAST has been equipped with two high power lower hybrid current drive (LHCD) systems operating frequencies of 2.45 GHz and 4.6 GHz. Comparative LHCD experiments the different were performed in same conditions plasma for first time. It was found that (CD) efficiency heating effect are much better LH waves than one High confinement mode (H-mode) discharges as sole auxiliary source have obtained is higher respect to produced previously by A combination ray-tracing Fokker-Planck calculations...
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...
Abstract The consequences of tungsten (W) melting on divertor lifetime and plasma operation are high priority issues for ITER. Sustained controlled W-melting experiment has been achieved the first time in WEST a poloidal sharp leading edge an actively cooled ITER-like facing unit (PFU). A series dedicated power steady state discharges were performed to reach point tungsten. was exposed parallel heat flux about 100 MW.m −2 up 5 s providing melt phase 2 without noticeable impact (radiated...
Abstract A recent EAST experiment has successfully demonstrated long pulse steady-state high plasma performance scenario and core-edge integration since the last IAEA in 2018. discharge with a duration over 60 s β P ∼ 2.0, N 1.6, H 98y2 1.3 an internal transport barrier on electron temperature channel is obtained multi-RF power heating current drive. higher ( 1.8, p 1.3, n e / GW 0.75) of 20 achieved by using modulated neutral beam power, where several normalized parameters are close or even...
Using a 2 MW 2.45 GHz lower hybrid wave (LHW) system installed in experimental advanced superconducting tokamak, we have systematically carried out LHW-plasma coupling and current drive experiments both divertor (double null single null) limiter plasma configuration with (Ip) ∼ 250 kA central line averaged density (ne) 1.0–1.3 × 1019 m−3 recently. Results show that the reflection coefficient (RC) first is flat up to some distance between LHW grill, then increases distance. Studies indicate...