A5056489410- Magnetic confinement fusion research
- Fusion materials and technologies
- Laser-induced spectroscopy and plasma
- Laser-Plasma Interactions and Diagnostics
- Ion-surface interactions and analysis
- Nuclear Materials and Properties
- Superconducting Materials and Applications
- Nuclear reactor physics and engineering
- Ionosphere and magnetosphere dynamics
- Plasma Diagnostics and Applications
- Atomic and Molecular Physics
- Particle accelerators and beam dynamics
- X-ray Spectroscopy and Fluorescence Analysis
- Analytical chemistry methods development
- Nuclear Physics and Applications
- Vacuum and Plasma Arcs
- Metal and Thin Film Mechanics
- Metallurgical Processes and Thermodynamics
- Marine Biology and Ecology Research
- High-Temperature Coating Behaviors
- Nuclear Engineering Thermal-Hydraulics
- Advanced Materials Characterization Techniques
- Anomaly Detection Techniques and Applications
- Advanced X-ray and CT Imaging
- Marine and coastal ecosystems
Aalto University
2014-2025
VTT Technical Research Centre of Finland
2012-2024
Helsinki Institute of Physics
2024
University of Helsinki
2021-2024
CEA Cadarache
2024
Culham Science Centre
2014-2023
Culham Centre for Fusion Energy
2022-2023
United Kingdom Atomic Energy Authority
2023
Royal Military Academy
2020
Dutch Institute for Fundamental Energy Research
2019
Analysis and understanding of wall erosion, material transport fuel retention are among the most important tasks for ITER future devices, since these questions determine largely lifetime availability fusion reactor. These data also extreme value to improve validate models in vessel build-up T inventory D–T devices. So far, research areas is supported by post-mortem analysis tiles. However, access samples will be very much restricted next-generation devices (such as ITER, JT-60SA, W7-X, etc)...
The provision of a particle and power exhaust solution which is compatible with first-wall components edge-plasma conditions key area present-day fusion research mandatory for successful operation ITER DEMO. work package plasma-facing (WP PFC) within the European programme complements laboratory experiments, i.e. in linear plasma devices, electron ion beam loading facilities, studies performed toroidally confined magnetic such as JET, ASDEX Upgrade, WEST etc. connection both groups done via...
Abstract Laser-induced breakdown spectroscopy (LIBS) is one of the most promising methods for quantitative in-situ determination fuel retention in plasma-facing components (PFCs) magnetically confined fusion devices like ITER and JET. In this article, current state understanding LIBS development applications will be presented, based on a complete review existing results complemented with newly obtained data. The work has been performed as part research programme, set up EUROfusion...
Abstract After the second Deuterium–Tritium Campaign (DTE2) in JET tokamak with ITER-Like Wall (ILW) and full tritium campaigns that preceded followed after DTE2, a sequence of fuel recovery methods was applied to promote removal from wall components. The started several days baking main chamber walls at 240 °C 320 °C. Subsequently, superimposed Ion-Cyclotron Conditioning (ICWC) Glow Discharge (GDC) cleaning cycles deuterium. Diverted plasma operation deuterium different strike point...
Abstract The dimensionless isotope mass scaling experiment between pure Deuterium and Tritium plasmas with matched <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mi>ρ</mml:mi> <mml:mo>∗</mml:mo> </mml:msup> </mml:math> , <mml:mi>ν</mml:mi> β n q <mml:msub> <mml:mi>T</mml:mi> <mml:mi>e</mml:mi> </mml:msub> <mml:mrow> <mml:mo>/</mml:mo> </mml:mrow> <mml:mi>i</mml:mi> has been achieved in JET L-mode dominant electron heating (NBI+ohmic) conditions....
Abstract This paper reports the first experiment carried out in deuterium–tritium addressing integration of a radiative divertor for heat-load control with good confinement. Neon seeding was time D–T plasma as part second campaign JET its Be/W wall environment. The technical difficulties linked to re-ionisation heat load are reported T and D–T. compares impact neon on plasmas their D counterpart detachment, localisation radiation, scrape-off profiles, pedestal structure, edge localised modes global
Abstract Building on prior analysis of ASDEX Upgrade (AUG) experiments (Henderson et al 2023 Nucl. Fusion 63 086024), this study compares simple analytical formula predictions for divertor detachment onset and reattachment timescales in JET experiments. Detachment primarily scales with neutral pressure, impurity concentration, power directed to the targets, machine size, integral perpendicular decay length. experiments, focusing seeding mixtures Ne Ar, align predictions. Radiation...
Abstract Deuterium (D) and beryllium (Be) fluxes are obtained in JET Low-confinement (L-mode) plasmas at the outer limiters of first wall using calibrated visible cameras. They inferred from measured radiances spectroscopic S/XB method. From fluxes, effective gross erosion yield Yeff limiter surface is estimated. After discussing uncertainties proposed methodology, we show dependence deduced particle recent L-mode on: separatrix-limiter clearance, magnetic field plasma current, NBI ICR...
The ablation and fuel-retention characteristics of aluminum–tungsten (AlW) beryllium–tungsten (BeW) samples have been determined using Laser Induced Breakdown Spectroscopy (LIBS) compared to results obtained Secondary Ion Mass Spectrometry (SIMS). measurements made both at vacuum (of the order 10−4 Pa) 50 Pa argon especially enhance intensities spectral lines H D. For reliable evaluation rate electron density ne temperature Te LIBS plasma with help selected Be, Al, W. has from Stark...
A remote LIBS system is being considered as an analysis tool in ITER for monitoring the erosion and fuel retention first wall. This necessitates further investigation of performance thick co-deposited layers consisting ITER-relevant materials. The main goal this work determining content samples D depth profile by to compare results with those obtained other methods. studied were Be-based mixed coatings on W substrates, containing some cases C, O, or both. These impurities are relevant not...
Recent measurements of the Lyβ/Dα ratio in JET ITER-like wall (ILW) divertor show comparatively more pronounced Lyβ reabsorption relative to previous results with carbon (JET-C). At outer horizontal target ion current rollover point a rate 60% is measured, increasing 80% detachment, implying Lyα 90-98%. The radially resolved are used constrain Lyman opacity corrections atomic coefficients using population escape factor technique order capture local changes excited state structure high...
Abstract In ITER, a remote handling laser-induced breakdown spectroscopy (LIBS) system is considered to be able observe regions where deposition of thick layers expected occur and assess the retention fuel on wall structures. The H D contents surface divertor first-wall materials have been intensely studied by LIBS but mostly depth profile analysis D. As far as we know, quantitative H/D in BeW mixed layer calibration free-LIBS (CF-LIBS) has not performed. Thus, aim this work quantification...
Abstract JET-ILW type I ELMy H-modes at 2.5 MA/2.8 T with constant NBI heating (23 MW) and gas fuelling rate were performed, utilising edge localised mode (ELM) pacing by vertical kicks plasma shaping (triangularity, δ ) as tools to disentangle the effects of ELMs, inter-ELM transport stability on pedestal particle balance. In agreement previous studies, confinement improves increasing , mostly due a significant increase in density while ELM frequency ( <?CDATA $f_{\mathrm{ELM}}$?> <mml:math...
Ray-tracing techniques are applied to filtered divertor imaging, a diagnostic that has long suffered from artifacts due the polluting effect of reflected light in metal walled fusion machines. Physically realistic surface reflections were modeled using Cook-Torrance micro-facet bi-directional reflection distribution function high resolution mesh vessel geometry. In absence gonioreflectometer measurements, technique was developed fit free parameters model against images JET in-vessel sources....
Considering reflections from metallic wall surfaces in generation of tomographic reconstructions the tangentially viewing, visible-range spectroscopic divertor cameras JET has been observed to yield enhanced spatial accuracy and significant reduction emission artifacts experimentally resolved 2D line distributions. Neglection tomography process was found lead overestimation near by up a factor 4, as well formation bright between main regions surfaces, comprising locally 50% emission....
Abstract A sequence of fuel recovery methods was tested in JET, equipped with the ITER-like beryllium main chamber wall and tungsten divertor, to reduce plasma deuterium concentration less than 1% preparation for operation tritium. This also a key activity regard refining clean-up strategy be implemented at end 2nd DT campaign JET (DTE2) assess tools that are envisaged mitigate tritium inventory build-up ITER. The began 4 days baking 320 °C, followed by further which Ion Cyclotron Wall...
AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsSpecials 68:267-272 (2013) - DOI: https://doi.org/10.3354/ame01620 Green sulphur bacteria as a component of photosynthetic plankton community in small dimictic humic lakes with an anoxic hypolimnion Jatta Karhunen1,*, Lauri Arvola2, Sari Peura1,3, Marja Tiirola1 1Department Biological and Environmental Science, University...
Measurements of the ion currents to and plasma conditions at low-field side (LFS) divertor target plate in low-confinement mode plasmas JET ITER-like wall materials configuration show that core density required detach LFS is independent hydrogenic species protium, deuterium tritium, a 40 %/60 % deuterium–tritium mixture. This observation applies with strike line connected horizontal part chosen because its superior diagnostic coverage. The finding operational status cryogenic pump. electron...
Laser Induced Breakdown Spectroscopy (LIBS) method is considered to be a promising tool for analyzing the retention of hydrogen isotopes (D and T) helium (He) on first walls divertor regions future fusion reactors. Helium will produced in DT reactions but could also used initial non-nuclear phases DEMO concepts. The present study investigates He detection by LIBS Be coatings simulating deposits plasma-facing components JET while results are relevant other wall materials. was carried out...
Abstract The experimental and theoretical analysis were focused on experiments conducted to assess the effect of plasma isotopes, protium (H), deuterium (D), tritium (T) ion cyclotron resonance heating (ICRH) related wall interactions. Comparison L-mode discharges with N = 1 3 He H minority ICRH scenarios done for different isotopes. For selected pulses, behaviour high-Z, mid-Z low-Z intrinsic impurity radiated power was investigated based data from VUV, visible spectroscopy, bolometry...
Laser-induced breakdown spectroscopy (LIBS) experiments on different ITER-relevant beryllium–tungsten mixtures were performed to develop LIBS for tokamak applications. Some of the samples doped or implanted with deuterium simulate fuel retention. The results indicate that beryllium and tungsten have a number distinguishable spectral lines diagnostics purposes, but detection is challenged by its low concentration fluences used. By studying depth profiles coatings, removal rates layers...