- EC| EUROfusion ,AKA| Fusion with a twist: Racing particles (also) in W7-X stellarator
Weckmann, A.; Kurki-Suonio, T.;Weckmann, A.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesWeckmann, A. in OpenAIRE
Särkimäki, Konsta; Särkimäki, Konsta
Harvested from ORCID Public Data FileSärkimäki, Konsta in OpenAIRE Romazanov, J.; +6 AuthorsRomazanov, J.
Harvested from ORCID Public Data FileRomazanov, J. in OpenAIRE Weckmann, A.; Kurki-Suonio, T.;Weckmann, A.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesWeckmann, A. in OpenAIRE Särkimäki, Konsta; Särkimäki, Konsta
Harvested from ORCID Public Data FileSärkimäki, Konsta in OpenAIRE Romazanov, J.; Kirschner, Andreas;Romazanov, J.
Harvested from ORCID Public Data FileRomazanov, J. in OpenAIRE Hakola, A.; Hakola, A.
Harvested from ORCID Public Data FileHakola, A. in OpenAIRE Airila, M.; Airila, M.
Harvested from ORCID Public Data FileAirila, M. in OpenAIRE Kreter, Arkadi; Brezinsek; Sebastijan;Kreter, Arkadi
Harvested from ORCID Public Data FileKreter, Arkadi in OpenAIREErosion, transport and deposition of wall impurities are major concerns in future magnetic fusion devices, both from the perspective of the fusion plasma and the machine wall. An extensive study on molybdenum transport and deposition performed in the TEXTOR tokamak yielded a detailed deposition map that is ideal for benchmark deposition studies. A qualitative benchmark is attempted in this article with the ASCOT code. We set up a full 3D model of the TEXTOR tokamak and studied the influence of different physical mechanisms and their strengths on molybdenum deposition patterns on the simulated plasma-facing components: atomic processes, Coulomb collisions, scrape-off layer (SOL) profiles, source distribution, marker starting energy, radial electric field strength, SOL flow and toroidal plasma rotation. The outcome comprises 13 simulations, each with 100,000 markers. The findings are: • Toroidal plasma movement, either within the LCFS or as SOL flow, is negligible. • SOL profile and marker starting energy have modest impact on deposition. • Source distribution has a large impact in combination with radial electric field profiles. • The E⇀×B⇀ drift has the highest impact on the deposition profiles.
Access RoutesGreen gold 1 citations 1 popularity Average influence Average impulse Average 
Powered by BIP!add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2019.02.033&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu - EC| EUROfusion ,AKA| Fusion with a twist: Racing particles (also) in W7-X stellarator Weckmann, A.; Kurki-Suonio, T.;
Weckmann, A.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesWeckmann, A. in OpenAIRE Särkimäki, Konsta; Särkimäki, Konsta
Harvested from ORCID Public Data FileSärkimäki, Konsta in OpenAIRE Romazanov, J.; +6 AuthorsRomazanov, J.
Harvested from ORCID Public Data FileRomazanov, J. in OpenAIRE Weckmann, A.; Kurki-Suonio, T.;Weckmann, A.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesWeckmann, A. in OpenAIRE Särkimäki, Konsta; Särkimäki, Konsta
Harvested from ORCID Public Data FileSärkimäki, Konsta in OpenAIRE Romazanov, J.; Kirschner, Andreas;Romazanov, J.
Harvested from ORCID Public Data FileRomazanov, J. in OpenAIRE Hakola, A.; Hakola, A.
Harvested from ORCID Public Data FileHakola, A. in OpenAIRE Airila, M.; Airila, M.
Harvested from ORCID Public Data FileAirila, M. in OpenAIRE Kreter, Arkadi; Brezinsek; Sebastijan;Kreter, Arkadi
Harvested from ORCID Public Data FileKreter, Arkadi in OpenAIREErosion, transport and deposition of wall impurities are major concerns in future magnetic fusion devices, both from the perspective of the fusion plasma and the machine wall. An extensive study on molybdenum transport and deposition performed in the TEXTOR tokamak yielded a detailed deposition map that is ideal for benchmark deposition studies. A qualitative benchmark is attempted in this article with the ASCOT code. We set up a full 3D model of the TEXTOR tokamak and studied the influence of different physical mechanisms and their strengths on molybdenum deposition patterns on the simulated plasma-facing components: atomic processes, Coulomb collisions, scrape-off layer (SOL) profiles, source distribution, marker starting energy, radial electric field strength, SOL flow and toroidal plasma rotation. The outcome comprises 13 simulations, each with 100,000 markers. The findings are: • Toroidal plasma movement, either within the LCFS or as SOL flow, is negligible. • SOL profile and marker starting energy have modest impact on deposition. • Source distribution has a large impact in combination with radial electric field profiles. • The E⇀×B⇀ drift has the highest impact on the deposition profiles.
Access RoutesGreen gold 1 citations 1 popularity Average influence Average impulse Average Powered by BIP!add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2019.02.033&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu - EC| EUROfusion Groth, Mathias; Heliste, Petteri;
Groth, Mathias
Harvested from ORCID Public Data FileGroth, Mathias in OpenAIRE Pütterich, Thomas; Pütterich, Thomas
Harvested from ORCID Public Data FilePütterich, Thomas in OpenAIRE Viezzer, Eleonora; +9 AuthorsViezzer, Eleonora
Harvested from ORCID Public Data FileViezzer, Eleonora in OpenAIRE Groth, Mathias; Heliste, Petteri;Groth, Mathias
Harvested from ORCID Public Data FileGroth, Mathias in OpenAIRE Pütterich, Thomas; Pütterich, Thomas
Harvested from ORCID Public Data FilePütterich, Thomas in OpenAIRE Viezzer, Eleonora; Viezzer, Eleonora
Harvested from ORCID Public Data FileViezzer, Eleonora in OpenAIRE Carralero, Daniel; Coster, David;Carralero, Daniel
Harvested from ORCID Public Data FileCarralero, Daniel in OpenAIRE Guimarais, Luis; Guimarais, Luis
Harvested from ORCID Public Data FileGuimarais, Luis in OpenAIRE Nikolaeva, Valentina; Nikolaeva, Valentina
Harvested from ORCID Public Data FileNikolaeva, Valentina in OpenAIRE Hakola, Antti; Potzel, Steffen; ASDEX Upgrade; team;Hakola, Antti
Harvested from ORCID Public Data FileHakola, Antti in OpenAIRE Karhunen, Juuso; Karhunen, Juuso
Harvested from ORCID Public Data FileKarhunen, Juuso in OpenAIREToroidal and poloidal flows of injected N+ ions were measured in the high-field side (HFS) scrape-off layer (SOL) of ASDEX Upgrade by Doppler spectroscopy with different degrees of HFS divertor detachment. In high-recycling conditions, the results suggest reversed parallel N+ flow away from the inner divertor in the near SOL close to the separatrix, while the flow is towards the inner divertor throughout the SOL in detached conditions. The measured poloidal N+ flows were directed away from the HFS divertor in the near SOL for all density cases. Divertor plasma oscillations, characterized by momentary peaking of the HFS target ion flux and decrease of the HFS SOL density, were observed slightly before the roll-over of the ion saturation current to the HFS target and lead to an increase in the N+ flow towards the HFS divertor. SOLPS and ERO simulations of the experiment predict entrainment below 50% between the velocities of N+ and D+ ions, suggesting that N+ ions are quantitatively a limited proxy for measuring D+ flows. ERO simulations show significantly higher entrainment for higher ionization states, e.g., N2+ and N3+.
Access RoutesGreen gold 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2017.02.020&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu - EC| EUROfusion Groth, Mathias; Heliste, Petteri;
Groth, Mathias
Harvested from ORCID Public Data FileGroth, Mathias in OpenAIRE Pütterich, Thomas; Pütterich, Thomas
Harvested from ORCID Public Data FilePütterich, Thomas in OpenAIRE Viezzer, Eleonora; +9 AuthorsViezzer, Eleonora
Harvested from ORCID Public Data FileViezzer, Eleonora in OpenAIRE Groth, Mathias; Heliste, Petteri;Groth, Mathias
Harvested from ORCID Public Data FileGroth, Mathias in OpenAIRE Pütterich, Thomas; Pütterich, Thomas
Harvested from ORCID Public Data FilePütterich, Thomas in OpenAIRE Viezzer, Eleonora; Viezzer, Eleonora
Harvested from ORCID Public Data FileViezzer, Eleonora in OpenAIRE Carralero, Daniel; Coster, David;Carralero, Daniel
Harvested from ORCID Public Data FileCarralero, Daniel in OpenAIRE Guimarais, Luis; Guimarais, Luis
Harvested from ORCID Public Data FileGuimarais, Luis in OpenAIRE Nikolaeva, Valentina; Nikolaeva, Valentina
Harvested from ORCID Public Data FileNikolaeva, Valentina in OpenAIRE Hakola, Antti; Potzel, Steffen; ASDEX Upgrade; team;Hakola, Antti
Harvested from ORCID Public Data FileHakola, Antti in OpenAIRE Karhunen, Juuso; Karhunen, Juuso
Harvested from ORCID Public Data FileKarhunen, Juuso in OpenAIREToroidal and poloidal flows of injected N+ ions were measured in the high-field side (HFS) scrape-off layer (SOL) of ASDEX Upgrade by Doppler spectroscopy with different degrees of HFS divertor detachment. In high-recycling conditions, the results suggest reversed parallel N+ flow away from the inner divertor in the near SOL close to the separatrix, while the flow is towards the inner divertor throughout the SOL in detached conditions. The measured poloidal N+ flows were directed away from the HFS divertor in the near SOL for all density cases. Divertor plasma oscillations, characterized by momentary peaking of the HFS target ion flux and decrease of the HFS SOL density, were observed slightly before the roll-over of the ion saturation current to the HFS target and lead to an increase in the N+ flow towards the HFS divertor. SOLPS and ERO simulations of the experiment predict entrainment below 50% between the velocities of N+ and D+ ions, suggesting that N+ ions are quantitatively a limited proxy for measuring D+ flows. ERO simulations show significantly higher entrainment for higher ionization states, e.g., N2+ and N3+.
Access RoutesGreen gold 0 citations 0 popularity Average influence Average impulse Average Powered by BIP!add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2017.02.020&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu - EC| EUROfusion Antti Hakola; A. Kallenbach; EUROfusion Mst Team; G. De Temmerman; +20 Authors
Antti Hakola
Harvested from ORCID Public Data FileAntti Hakola in OpenAIRE Antti Hakola; A. Kallenbach; EUROfusion Mst Team; G. De Temmerman; B. Sieglin;Antti Hakola
Harvested from ORCID Public Data FileAntti Hakola in OpenAIRE S. Brezinsek; S. Elgeti; H. Mayer; D. Brida;S. Brezinsek
Harvested from ORCID Public Data FileS. Brezinsek in OpenAIRE R. Neu; K. Krieger; M. Balden;K. Krieger
Harvested from ORCID Public Data FileK. Krieger in OpenAIRE V. Rohde; Ch. Linsmeier; R. Caniello; S. Potzel; Gerd Meisl; D. Carralero; H. Greuner;D. Carralero
Harvested from ORCID Public Data FileD. Carralero in OpenAIRE M. Oberkofler; Alexis Terra;M. Oberkofler
Harvested from ORCID Public Data FileM. Oberkofler in OpenAIRE A. Lahtinen; B. Böswirth;A. Lahtinen
Harvested from ORCID Public Data FileA. Lahtinen in OpenAIRE D. Douai; Tungsten (W) will be used as material for plasma-facing components (PFCs) in the divertor of ITER and interact with Helium (He) ions either from initial He plasma operation or from Deuterium-Tritium (DT) fusion reactions in the active operation phase. Laboratory experiments reported that in a specific operational window of impact energy, ion fluence, and surface temperature (E in ≥ 20 eV, φ ≥ 1 × 1024 He+mBt=2.5T, Ip=0.8MA, Paux ≃ 8.0MW Tsurf ≥ 1000 K) a modification of W surfaces occurs resulting in the formation of He-induced W nanostructures. Experiments in ASDEX Upgrade H-mode plasmas (Ein=37keV T, φ ≃ 0.75×1024 He0m−2 MA, Paux ≃ 8.0 MW) in He have been carried out to investigate in detail (a) the potential growth of W nanostructures on pre-damaged W samples incorporating He nanobubbles, and (b) the potential ELM-induced erosion of W nanostructure. Both W surface modifications were generated artificially in the GLADIS facility by He bombardment of W samples at φ ≃ 1×1024 He0m−2 keV (a) to φ ≃ 0.75 × 1024 He0m φ ≃ 1.6×1024 He+m−2 at Tsurf ≃ 1800 K and (b) φ ≃ 1 × 1024 He0m−2 at Tsurf ≃ 2300 K prior to exposure in the divertor manipulator of ASDEX Upgrade. Though in part (a) conditions of W nanostructure growth with a total He ion fluence of φ ≃ 1.6 × 1024 He+m−2 and peak He ion impact energies above 150 eV were met, no growth could be detected. In part (b) lower density plasmas with more pronounced type I ELMs, carrying energetic He ions in the keV range, were executed with the strike-line positioned on 2 µm thick W nanostructure accumulating a fluence of φ ≃ 0.8 × 1024 He+m−2. Post-mortem analysis revealed that co-deposition by predominantly W, and Boron (B), eroded at the main chamber wall and transported into the divertor, took place on all W samples. Erosion of W nanostructure or its formation was hindered by the fact that the outer divertor at the location of the samples was turned under these He plasma conditions into a net deposition zone by W, B and Carbon (C) ions. The surface morphology with large roughness and effective surface area act as a catcher for the impinging impurities. Thus, apart from operation in the existence diagram of W nanostructure with respect to Tsurf, φ, and Ein, also the impinging impurity flux contribution needs to be considered in predictions concerning the formation of W nanostructures.
Access RoutesGreen gold 25 citations 25 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2016.11.002&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu - EC| EUROfusion Antti Hakola; A. Kallenbach; EUROfusion Mst Team; G. De Temmerman; +20 Authors
Antti Hakola
Harvested from ORCID Public Data FileAntti Hakola in OpenAIRE Antti Hakola; A. Kallenbach; EUROfusion Mst Team; G. De Temmerman; B. Sieglin;Antti Hakola
Harvested from ORCID Public Data FileAntti Hakola in OpenAIRE S. Brezinsek; S. Elgeti; H. Mayer; D. Brida;S. Brezinsek
Harvested from ORCID Public Data FileS. Brezinsek in OpenAIRE R. Neu; K. Krieger; M. Balden;K. Krieger
Harvested from ORCID Public Data FileK. Krieger in OpenAIRE V. Rohde; Ch. Linsmeier; R. Caniello; S. Potzel; Gerd Meisl; D. Carralero; H. Greuner;D. Carralero
Harvested from ORCID Public Data FileD. Carralero in OpenAIRE M. Oberkofler; Alexis Terra;M. Oberkofler
Harvested from ORCID Public Data FileM. Oberkofler in OpenAIRE A. Lahtinen; B. Böswirth;A. Lahtinen
Harvested from ORCID Public Data FileA. Lahtinen in OpenAIRE D. Douai; Tungsten (W) will be used as material for plasma-facing components (PFCs) in the divertor of ITER and interact with Helium (He) ions either from initial He plasma operation or from Deuterium-Tritium (DT) fusion reactions in the active operation phase. Laboratory experiments reported that in a specific operational window of impact energy, ion fluence, and surface temperature (E in ≥ 20 eV, φ ≥ 1 × 1024 He+mBt=2.5T, Ip=0.8MA, Paux ≃ 8.0MW Tsurf ≥ 1000 K) a modification of W surfaces occurs resulting in the formation of He-induced W nanostructures. Experiments in ASDEX Upgrade H-mode plasmas (Ein=37keV T, φ ≃ 0.75×1024 He0m−2 MA, Paux ≃ 8.0 MW) in He have been carried out to investigate in detail (a) the potential growth of W nanostructures on pre-damaged W samples incorporating He nanobubbles, and (b) the potential ELM-induced erosion of W nanostructure. Both W surface modifications were generated artificially in the GLADIS facility by He bombardment of W samples at φ ≃ 1×1024 He0m−2 keV (a) to φ ≃ 0.75 × 1024 He0m φ ≃ 1.6×1024 He+m−2 at Tsurf ≃ 1800 K and (b) φ ≃ 1 × 1024 He0m−2 at Tsurf ≃ 2300 K prior to exposure in the divertor manipulator of ASDEX Upgrade. Though in part (a) conditions of W nanostructure growth with a total He ion fluence of φ ≃ 1.6 × 1024 He+m−2 and peak He ion impact energies above 150 eV were met, no growth could be detected. In part (b) lower density plasmas with more pronounced type I ELMs, carrying energetic He ions in the keV range, were executed with the strike-line positioned on 2 µm thick W nanostructure accumulating a fluence of φ ≃ 0.8 × 1024 He+m−2. Post-mortem analysis revealed that co-deposition by predominantly W, and Boron (B), eroded at the main chamber wall and transported into the divertor, took place on all W samples. Erosion of W nanostructure or its formation was hindered by the fact that the outer divertor at the location of the samples was turned under these He plasma conditions into a net deposition zone by W, B and Carbon (C) ions. The surface morphology with large roughness and effective surface area act as a catcher for the impinging impurities. Thus, apart from operation in the existence diagram of W nanostructure with respect to Tsurf, φ, and Ein, also the impinging impurity flux contribution needs to be considered in predictions concerning the formation of W nanostructures.
Access RoutesGreen gold 25 citations 25 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2016.11.002&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu - EC| EUROfusionMeisl, G.; Oberkofler, M.;
Oberkofler, M.
Harvested from ORCID Public Data FileOberkofler, M. in OpenAIRE Hakola, A.; Hakola, A.
Harvested from ORCID Public Data FileHakola, A. in OpenAIRE Krieger, K.; +9 AuthorsKrieger, K.
Harvested from ORCID Public Data FileKrieger, K. in OpenAIREMeisl, G.; Oberkofler, M.; Oberkofler, M.
Harvested from ORCID Public Data FileOberkofler, M. in OpenAIRE Hakola, A.; Hakola, A.
Harvested from ORCID Public Data FileHakola, A. in OpenAIRE Krieger, K.; Schmid, K.; Lisgo, S.W.;Krieger, K.
Harvested from ORCID Public Data FileKrieger, K. in OpenAIRE Mayer, M.; Lahtinen, A.; Drenik, A.; Potzel, S.;Lahtinen, A.
Harvested from ORCID Public Data FileLahtinen, A. in OpenAIRE Aho-Mantila, L.; Team; A.S.D.E.X.U. ;Aho-Mantila, L.
Harvested from ORCID Public Data FileAho-Mantila, L. in OpenAIREWe have studied the retention of nitrogen in surfaces with varying roughness and the transport of nitrogen from the divertor to the outer midplane in experiments at the tokamak ASDEX Upgrade. To allow for a reliable identification of nitrogen retained from the plasma exposure, 5.3 · 1021 atoms of the tracer isotope 15N were injected into the private flux region of the plasma. On polished W samples exposed to the plasma in the outer divertor, the N content peaks to both sides of the strike line with an areal density of 1.5 · 1020 15N/m2 and drops to a value of 1.0 · 1020 15N/m2 in the strike line region. In contrast, the N content of samples with a rougher surface peaks at the strike line and reaches areal densities of 3.0 · 1020 15N/m2. The N deposition at the outer limiters was measured via samples exposed on the midplane manipulator. At the limiter position the 15N areal density reaches a value of 0.2 · 1020 15N/m2, only a factor of ten smaller than the areal densities in the divertor. However, a comparison to WallDYN simulations shows that the observed N content is roughly a factor of 4 smaller than the value predicted by these simulations. Possible reasons for this discrepancy are the toroidal asymmetric main wall geometry, which currently cannot be fully included in the simulations, or an enhanced re-erosion of deposited N.
Access Routesgold 8 citations 8 popularity Top 10% influence Average impulse Top 10% Powered by BIP!add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2016.10.023&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu - EC| EUROfusionMeisl, G.; Oberkofler, M.;
Oberkofler, M.
Harvested from ORCID Public Data FileOberkofler, M. in OpenAIRE Hakola, A.; Hakola, A.
Harvested from ORCID Public Data FileHakola, A. in OpenAIRE Krieger, K.; +9 AuthorsKrieger, K.
Harvested from ORCID Public Data FileKrieger, K. in OpenAIREMeisl, G.; Oberkofler, M.; Oberkofler, M.
Harvested from ORCID Public Data FileOberkofler, M. in OpenAIRE Hakola, A.; Hakola, A.
Harvested from ORCID Public Data FileHakola, A. in OpenAIRE Krieger, K.; Schmid, K.; Lisgo, S.W.;Krieger, K.
Harvested from ORCID Public Data FileKrieger, K. in OpenAIRE Mayer, M.; Lahtinen, A.; Drenik, A.; Potzel, S.;Lahtinen, A.
Harvested from ORCID Public Data FileLahtinen, A. in OpenAIRE Aho-Mantila, L.; Team; A.S.D.E.X.U. ;Aho-Mantila, L.
Harvested from ORCID Public Data FileAho-Mantila, L. in OpenAIREWe have studied the retention of nitrogen in surfaces with varying roughness and the transport of nitrogen from the divertor to the outer midplane in experiments at the tokamak ASDEX Upgrade. To allow for a reliable identification of nitrogen retained from the plasma exposure, 5.3 · 1021 atoms of the tracer isotope 15N were injected into the private flux region of the plasma. On polished W samples exposed to the plasma in the outer divertor, the N content peaks to both sides of the strike line with an areal density of 1.5 · 1020 15N/m2 and drops to a value of 1.0 · 1020 15N/m2 in the strike line region. In contrast, the N content of samples with a rougher surface peaks at the strike line and reaches areal densities of 3.0 · 1020 15N/m2. The N deposition at the outer limiters was measured via samples exposed on the midplane manipulator. At the limiter position the 15N areal density reaches a value of 0.2 · 1020 15N/m2, only a factor of ten smaller than the areal densities in the divertor. However, a comparison to WallDYN simulations shows that the observed N content is roughly a factor of 4 smaller than the value predicted by these simulations. Possible reasons for this discrepancy are the toroidal asymmetric main wall geometry, which currently cannot be fully included in the simulations, or an enhanced re-erosion of deposited N.
Access Routesgold 8 citations 8 popularity Top 10% influence Average impulse Top 10% Powered by BIP!add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2016.10.023&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu - EC| EUROfusionKeitaanranta, A.; Kumpulainen, Heikki; Lahtinen, Aapeli; Likonen, Jari; Balden, M.; Cavedon, M.; Krieger, K.;
Cavedon, M.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesCavedon, M. in OpenAIRE Airila, Markus; Groth, M.; ASDEX Upgrade Team; EUROfusion MST1 Team;Airila, Markus
Harvested from ORCID Public Data FileAirila, Markus in OpenAIRE Hakola, Antti; Hakola, Antti
Harvested from ORCID Public Data FileHakola, Antti in OpenAIREIn this paper, we report experimental and numerical investigations of gross and net erosion of gold (Au) and molybdenum (Mo), proxies for the common plasma-facing material tungsten (W), during L-mode plasma discharges in deuterium (D) in the outer strike-point region of the ASDEX Upgrade tokamak. To this end, erosion profiles of different marker spots (for Au, dimensions 1 × 1 and 5 × 5 mm2) and marker coatings (for Mo) have been determined and modelled using the ERO code. The smaller marker spots were designed to quantify the gross-erosion rate while on the bigger markers local prompt re-deposition of Au allowed obtaining data on net erosion. The experimental results indicate relatively uniform erosion profiles across the marker spots or coatings, very little re-deposition elsewhere, and the largest erosion taking place close to the strike point. Compared to W, the markers show up to 15 times higher net erosion but no major differences in the poloidal migration lengths of Au and W can be seen. Gold thus appears to be a proper choice for studying migration of W in the divertor region. The ERO simulations with different background plasmas are able to reproduce the main features of the experimental net erosion profile of Au. Of the studied parameters, electron temperature has the strongest impact on erosion: doubling the temperature enhances erosion by a factor of 2.5–3. In contrast, for Mo, the simulated net erosion is ~ 3 times smaller than what experimental data indicate. The discrepancies can be attributed to the deviations of the background plasma profiles from the measured ones as well as to the applied models or approximations for the ion temperature, plasma potential, and sheath characteristics in ERO. In addition, the surrounding areas of the marker samples being covered with impurities and W from previous experiments may have considerably reduced the actual re-deposition of Mo. All the simulations predict a toroidal tail of re-deposited particles, downstream of the markers, but the particle density seems to be below the experimental detection threshold. The comparison between the 1 × 1 mm2 and 5 × 5 mm2 marker spots further reveal that re-deposition drops from >50% to <40% when decreasing the marker size. This indicates that small enough marker samples can be used for accurately determining gross erosion in ASDEX Upgrade.
Access RoutesGreen gold 1 citations 1 popularity Average influence Average impulse Average Powered by BIP!add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2020.100863&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu - EC| EUROfusionKeitaanranta, A.; Kumpulainen, Heikki; Lahtinen, Aapeli; Likonen, Jari; Balden, M.; Cavedon, M.; Krieger, K.;
Cavedon, M.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesCavedon, M. in OpenAIRE Airila, Markus; Groth, M.; ASDEX Upgrade Team; EUROfusion MST1 Team;Airila, Markus
Harvested from ORCID Public Data FileAirila, Markus in OpenAIRE Hakola, Antti; Hakola, Antti
Harvested from ORCID Public Data FileHakola, Antti in OpenAIREIn this paper, we report experimental and numerical investigations of gross and net erosion of gold (Au) and molybdenum (Mo), proxies for the common plasma-facing material tungsten (W), during L-mode plasma discharges in deuterium (D) in the outer strike-point region of the ASDEX Upgrade tokamak. To this end, erosion profiles of different marker spots (for Au, dimensions 1 × 1 and 5 × 5 mm2) and marker coatings (for Mo) have been determined and modelled using the ERO code. The smaller marker spots were designed to quantify the gross-erosion rate while on the bigger markers local prompt re-deposition of Au allowed obtaining data on net erosion. The experimental results indicate relatively uniform erosion profiles across the marker spots or coatings, very little re-deposition elsewhere, and the largest erosion taking place close to the strike point. Compared to W, the markers show up to 15 times higher net erosion but no major differences in the poloidal migration lengths of Au and W can be seen. Gold thus appears to be a proper choice for studying migration of W in the divertor region. The ERO simulations with different background plasmas are able to reproduce the main features of the experimental net erosion profile of Au. Of the studied parameters, electron temperature has the strongest impact on erosion: doubling the temperature enhances erosion by a factor of 2.5–3. In contrast, for Mo, the simulated net erosion is ~ 3 times smaller than what experimental data indicate. The discrepancies can be attributed to the deviations of the background plasma profiles from the measured ones as well as to the applied models or approximations for the ion temperature, plasma potential, and sheath characteristics in ERO. In addition, the surrounding areas of the marker samples being covered with impurities and W from previous experiments may have considerably reduced the actual re-deposition of Mo. All the simulations predict a toroidal tail of re-deposited particles, downstream of the markers, but the particle density seems to be below the experimental detection threshold. The comparison between the 1 × 1 mm2 and 5 × 5 mm2 marker spots further reveal that re-deposition drops from >50% to <40% when decreasing the marker size. This indicates that small enough marker samples can be used for accurately determining gross erosion in ASDEX Upgrade.
Access RoutesGreen gold 1 citations 1 popularity Average influence Average impulse Average Powered by BIP!add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2020.100863&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu - FCT| Institute for Plasmas and Nuclear Fusion ,EC| EUROfusion Mateus, R.;
Mateus, R.
Harvested from ORCID Public Data FileMateus, R. in OpenAIRE Porosnicu, C.; Lungu, C.P.; Cruz, C.; +4 AuthorsPorosnicu, C.
Harvested from ORCID Public Data FilePorosnicu, C. in OpenAIRE Mateus, R.; Mateus, R.
Harvested from ORCID Public Data FileMateus, R. in OpenAIRE Porosnicu, C.; Lungu, C.P.; Cruz, C.; Siketić, Z.;Porosnicu, C.
Harvested from ORCID Public Data FilePorosnicu, C. in OpenAIRE Radović, I. Bogdanović; Radović, I. Bogdanović
Harvested from ORCID Public Data FileRadović, I. Bogdanović in OpenAIRE Hakola, A.; Hakola, A.
Harvested from ORCID Public Data FileHakola, A. in OpenAIRE Alves, E.; Pure Be, Be-O and Be-O-C thin coatings were deposited using high-power impulse magnetron sputtering (HiPIMS) with and without incorporation of deuterium. The coatings produced without deuterium were implanted afterwards with 15 keV 2H+ ion beams with a fluence limited to 2 × 1017 ion/cm2 in order to mitigate the damage imposed by ion irradiation and prevent a fast gas release. The as- deposited and as-implanted coatings were analysed by IBA techniques, namely by elastic and Rutherford backscattering spectrometries (EBS and RBS, respectively), nuclear reaction analysis (NRA) and by time-of-flight elastic recoil detection analysis (ToF-ERDA). Despite distinct deuterium depth profiles in the implanted samples, the results show that for the present ion implantation and deposition parameters, similar retained amounts are revealed in the films loaded by ion implantation or during the HiPIMS deposition, assuring ion implantation as a competitive and reliable method for fuel incorporation in thin Be-based films for retention studies in controlled conditions.
Access RoutesGreen gold add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2018.10.007&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu - FCT| Institute for Plasmas and Nuclear Fusion ,EC| EUROfusion Mateus, R.;
Mateus, R.
Harvested from ORCID Public Data FileMateus, R. in OpenAIRE Porosnicu, C.; Lungu, C.P.; Cruz, C.; +4 AuthorsPorosnicu, C.
Harvested from ORCID Public Data FilePorosnicu, C. in OpenAIRE Mateus, R.; Mateus, R.
Harvested from ORCID Public Data FileMateus, R. in OpenAIRE Porosnicu, C.; Lungu, C.P.; Cruz, C.; Siketić, Z.;Porosnicu, C.
Harvested from ORCID Public Data FilePorosnicu, C. in OpenAIRE Radović, I. Bogdanović; Radović, I. Bogdanović
Harvested from ORCID Public Data FileRadović, I. Bogdanović in OpenAIRE Hakola, A.; Hakola, A.
Harvested from ORCID Public Data FileHakola, A. in OpenAIRE Alves, E.; Pure Be, Be-O and Be-O-C thin coatings were deposited using high-power impulse magnetron sputtering (HiPIMS) with and without incorporation of deuterium. The coatings produced without deuterium were implanted afterwards with 15 keV 2H+ ion beams with a fluence limited to 2 × 1017 ion/cm2 in order to mitigate the damage imposed by ion irradiation and prevent a fast gas release. The as- deposited and as-implanted coatings were analysed by IBA techniques, namely by elastic and Rutherford backscattering spectrometries (EBS and RBS, respectively), nuclear reaction analysis (NRA) and by time-of-flight elastic recoil detection analysis (ToF-ERDA). Despite distinct deuterium depth profiles in the implanted samples, the results show that for the present ion implantation and deposition parameters, similar retained amounts are revealed in the films loaded by ion implantation or during the HiPIMS deposition, assuring ion implantation as a competitive and reliable method for fuel incorporation in thin Be-based films for retention studies in controlled conditions.
Access RoutesGreen gold add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2018.10.007&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu - FCT| Institute for Plasmas and Nuclear Fusion ,EC| EUROfusion Mateus, R.;
Mateus, R.
Harvested from ORCID Public Data FileMateus, R. in OpenAIRE Sequeira, M.C.; Sequeira, M.C.
Harvested from ORCID Public Data FileSequeira, M.C. in OpenAIRE Porosnicu, C.; Lungu, C.P.; +3 AuthorsPorosnicu, C.
Harvested from ORCID Public Data FilePorosnicu, C. in OpenAIRE Mateus, R.; Mateus, R.
Harvested from ORCID Public Data FileMateus, R. in OpenAIRE Sequeira, M.C.; Sequeira, M.C.
Harvested from ORCID Public Data FileSequeira, M.C. in OpenAIRE Porosnicu, C.; Lungu, C.P.;Porosnicu, C.
Harvested from ORCID Public Data FilePorosnicu, C. in OpenAIRE Hakola, A.; Alves; E. ;Hakola, A.
Harvested from ORCID Public Data FileHakola, A. in OpenAIREPure Be, W and Be:W mixed coatings with nominal compositions of (5:5) and (1:9) were deposited on silicon plates and implanted at room temperature with 30 keV N+ ions with fluences up to 5e17 ions/cm2. Ion beam and X-ray diffraction analysis evidenced the formation of the α-Be3N2 and β-W2N nitrides. The identified tungsten nitride phase evolves from a BCC W lattice to a BCC W(N) solid solution after irradiating at a fluence of 1e17 N+/cm2 and to the compact FCC β-W2N structure at 5e17 N+/cm2. Thermal stability of β-W2N was investigated by annealing the coatings for 1 h up to 1073 K. The results point to the release of non-bonded nitrogen solute in β-W2N over the annealing range and to the thermal stability of the nitride phase up to 1073 K.
Access Routesgold 19 citations 19 popularity Top 10% influence Average impulse Top 10% Powered by BIP!add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2017.03.040&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu - FCT| Institute for Plasmas and Nuclear Fusion ,EC| EUROfusion Mateus, R.;
Mateus, R.
Harvested from ORCID Public Data FileMateus, R. in OpenAIRE Sequeira, M.C.; Sequeira, M.C.
Harvested from ORCID Public Data FileSequeira, M.C. in OpenAIRE Porosnicu, C.; Lungu, C.P.; +3 AuthorsPorosnicu, C.
Harvested from ORCID Public Data FilePorosnicu, C. in OpenAIRE Mateus, R.; Mateus, R.
Harvested from ORCID Public Data FileMateus, R. in OpenAIRE Sequeira, M.C.; Sequeira, M.C.
Harvested from ORCID Public Data FileSequeira, M.C. in OpenAIRE Porosnicu, C.; Lungu, C.P.;Porosnicu, C.
Harvested from ORCID Public Data FilePorosnicu, C. in OpenAIRE Hakola, A.; Alves; E. ;Hakola, A.
Harvested from ORCID Public Data FileHakola, A. in OpenAIREPure Be, W and Be:W mixed coatings with nominal compositions of (5:5) and (1:9) were deposited on silicon plates and implanted at room temperature with 30 keV N+ ions with fluences up to 5e17 ions/cm2. Ion beam and X-ray diffraction analysis evidenced the formation of the α-Be3N2 and β-W2N nitrides. The identified tungsten nitride phase evolves from a BCC W lattice to a BCC W(N) solid solution after irradiating at a fluence of 1e17 N+/cm2 and to the compact FCC β-W2N structure at 5e17 N+/cm2. Thermal stability of β-W2N was investigated by annealing the coatings for 1 h up to 1073 K. The results point to the release of non-bonded nitrogen solute in β-W2N over the annealing range and to the thermal stability of the nitride phase up to 1073 K.
Access Routesgold 19 citations 19 popularity Top 10% influence Average impulse Top 10% Powered by BIP!add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2017.03.040&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu - EC| EUROfusion Vuoriheimo, Tomi;
Vuoriheimo, Tomi
Harvested from ORCID Public Data FileVuoriheimo, Tomi in OpenAIRE Hakola, Antti; Likonen, Jari; Krieger, Karl; +7 AuthorsHakola, Antti
Harvested from ORCID Public Data FileHakola, Antti in OpenAIRE Vuoriheimo, Tomi; Vuoriheimo, Tomi
Harvested from ORCID Public Data FileVuoriheimo, Tomi in OpenAIRE Hakola, Antti; Likonen, Jari; Krieger, Karl; Balden, Martin;Hakola, Antti
Harvested from ORCID Public Data FileHakola, Antti in OpenAIRE Bogdanović Radović, Iva; Provatas, Georgios; Siketić, Zdravko;Bogdanović Radović, Iva
Harvested from ORCID Public Data FileBogdanović Radović, Iva in OpenAIRE Ivanković Nizić, Karla; Rasinski, Marcin; Brezinsek, Sebastijan;Ivanković Nizić, Karla
Harvested from ORCID Public Data FileIvanković Nizić, Karla in OpenAIREThe effect of helium plasma operation on the erosion of plasma-facing components at the low-field side divertor of ASDEX Upgrade was investigated during the 2022 helium experimental campaign. A set of tungsten-covered graphite samples with small platinum marker spots was exposed to both L-mode and H-mode plasma discharges. The highest net erosion of over 1.1 nm/s was observed around the H-mode strike point similar to the case in deuterium plasma. Significant helium inventories of about 6 × 1016 He/cm2 were measured in the scrape-off layer region of the divertor. Impurity deposition including boron and deuterium showed a distinct peak up to 2.4 × 1017 B/cm2 and 1.0 × 1016 D/cm2 between the strike points, and significant boron inventories up to 5.9 × 1016 B/cm2 were also measured on the scrape-off layer side of the H-mode strike point. Platinum re-deposition was not detected between the marker spots, suggesting that it occurs only very locally within the markers. Overall erosion was, as expected, higher than in deuterium discharges, and it also remained comparatively high towards the scrape-off layer, unlike with deuterium.
Access Routesgold 1 citations 1 popularity Average influence Average impulse Average Powered by BIP!add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2024.101766&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu - EC| EUROfusion Vuoriheimo, Tomi;
Vuoriheimo, Tomi
Harvested from ORCID Public Data FileVuoriheimo, Tomi in OpenAIRE Hakola, Antti; Likonen, Jari; Krieger, Karl; +7 AuthorsHakola, Antti
Harvested from ORCID Public Data FileHakola, Antti in OpenAIRE Vuoriheimo, Tomi; Vuoriheimo, Tomi
Harvested from ORCID Public Data FileVuoriheimo, Tomi in OpenAIRE Hakola, Antti; Likonen, Jari; Krieger, Karl; Balden, Martin;Hakola, Antti
Harvested from ORCID Public Data FileHakola, Antti in OpenAIRE Bogdanović Radović, Iva; Provatas, Georgios; Siketić, Zdravko;Bogdanović Radović, Iva
Harvested from ORCID Public Data FileBogdanović Radović, Iva in OpenAIRE Ivanković Nizić, Karla; Rasinski, Marcin; Brezinsek, Sebastijan;Ivanković Nizić, Karla
Harvested from ORCID Public Data FileIvanković Nizić, Karla in OpenAIREThe effect of helium plasma operation on the erosion of plasma-facing components at the low-field side divertor of ASDEX Upgrade was investigated during the 2022 helium experimental campaign. A set of tungsten-covered graphite samples with small platinum marker spots was exposed to both L-mode and H-mode plasma discharges. The highest net erosion of over 1.1 nm/s was observed around the H-mode strike point similar to the case in deuterium plasma. Significant helium inventories of about 6 × 1016 He/cm2 were measured in the scrape-off layer region of the divertor. Impurity deposition including boron and deuterium showed a distinct peak up to 2.4 × 1017 B/cm2 and 1.0 × 1016 D/cm2 between the strike points, and significant boron inventories up to 5.9 × 1016 B/cm2 were also measured on the scrape-off layer side of the H-mode strike point. Platinum re-deposition was not detected between the marker spots, suggesting that it occurs only very locally within the markers. Overall erosion was, as expected, higher than in deuterium discharges, and it also remained comparatively high towards the scrape-off layer, unlike with deuterium.
Access Routesgold 1 citations 1 popularity Average influence Average impulse Average Powered by BIP!add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2024.101766&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu - EC| EUROfusion Gallo, A.; Moreau, Ph.;
Gallo, A.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesGallo, A. in OpenAIRE Douai, D.; Alarcon, T.; +26 Authors Gallo, A.; Moreau, Ph.;Gallo, A.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesGallo, A. in OpenAIRE Douai, D.; Alarcon, T.; Afonin, K.; Anzallo, V.; Bisson, R.; Bucalossi, J.; Caprin, E.; Corre, Y.; de Combarieu, M.; Desgranges, C.;Bisson, R.
Harvested from ORCID Public Data FileBisson, R. in OpenAIRE Devynck, P.; Devynck, P.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesDevynck, P. in OpenAIRE Ekedahl, A.; Ekedahl, A.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesEkedahl, A. in OpenAIRE Fedorczak, N.; Fedorczak, N.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesFedorczak, N. in OpenAIRE Gaspar, J.; Gaspar, J.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesGaspar, J. in OpenAIRE Grosjean, A.; Grosjean, A.
Harvested from ORCID Public Data FileGrosjean, A. in OpenAIRE Guillemaut, C.; Guirlet, R.; Gunn, J.P.; Hillairet, J.; Loarer, T.;Guillemaut, C.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesGuillemaut, C. in OpenAIRE Maget, P.; Manas, P.;Maget, P.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesMaget, P. in OpenAIRE Morales, J.; Pellissier, F.P.; Tsitrone, E.;Morales, J.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesMorales, J. in OpenAIRE Krieger, K.; Krieger, K.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesKrieger, K. in OpenAIRE Hakola, A.; Hakola, A.
Harvested from ORCID Public Data FileHakola, A. in OpenAIRE Widdowson, A.; Widdowson, A.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesWiddowson, A. in OpenAIREFuture fusion reactors like ITER and DEMO will have all-tungsten (W) walls and long pulses. These features will make wall conditioning more difficult than in most of the existing devices. The W Environment Steady-state Tokamak (WEST) is one of the few long pulse (364 s) fusion devices with actively cooled W plasma-facing components in the world. WEST is a unique test bed to study impurity migration and plasma density control via reactor relevant wall conditioning techniques. The phase II of WEST operations began in 2022, after the installation of a new lower divertor, now entirely equipped with actively cooled, ITER grade, W monoblocks. After pump down, we baked WEST between 90 °C and 170 °C for ∼2 weeks. After 82.5 h at 90 °C and 33 h at 170 °C, vacuum conditions were stable with a vessel pressure of 6x10-5 Pa and mass spectra dominated by H2 molecules. While at 170 °C, we performed ∼40 h of D2 glow discharge cleaning (GDC) and ∼5 h of glow discharge boronization (GDB), using a 15 %-85 % B2D6-He mix and a total boron mass of ∼12 g. This was the very first GDB at such high temperature for WEST. The whole wall conditioning sequence led to a ∼10 times reduction of the H2O signal as well as to a ∼3 times reduction of the O2 signal, according to mass spectra. Once back to 70 °C, the vessel pressure was 5.5x10-6 Pa and plasma restart was seamless with ∼30 s cumulated over the very first 5 pulses and an Ohmic radiated power fraction Frad = 0.6, showing successful conditioning of the new ITER grade divertor. The effect of the first, ‘hot’ GDB faded with a characteristic cumulative injected energy of 2.45 GJ and saturation towards Frad ∼0.8. After 1.4 h and 7.5 GJ of cumulative plasma time and injected energy, we carried out a second GDB, this time at 70 °C. This ‘cold’ GDB initially led to a much lower Ohmic Frad = 0.3–0.4 but the effect lasted ∼7 times less, with a characteristic cumulative injected energy of 0.37 GJ. At the end of the campaign, we cumulated ∼3h and ∼30 GJ through repetitive, minute long pulses without any boronization. Throughout this 4-weeks-long experiment, Frad in the 4 MW heating phase evolved only marginally (from 0.5 to 0.55). This increase is mostly due to the build-up of re/co-deposited layers on both lower divertor targets.
Access RoutesGreen gold 6 citations 6 popularity Average influence Average impulse Top 10% Powered by BIP!add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2024.101741&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu - EC| EUROfusion Gallo, A.; Moreau, Ph.;
Gallo, A.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesGallo, A. in OpenAIRE Douai, D.; Alarcon, T.; +26 Authors Gallo, A.; Moreau, Ph.;Gallo, A.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesGallo, A. in OpenAIRE Douai, D.; Alarcon, T.; Afonin, K.; Anzallo, V.; Bisson, R.; Bucalossi, J.; Caprin, E.; Corre, Y.; de Combarieu, M.; Desgranges, C.;Bisson, R.
Harvested from ORCID Public Data FileBisson, R. in OpenAIRE Devynck, P.; Devynck, P.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesDevynck, P. in OpenAIRE Ekedahl, A.; Ekedahl, A.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesEkedahl, A. in OpenAIRE Fedorczak, N.; Fedorczak, N.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesFedorczak, N. in OpenAIRE Gaspar, J.; Gaspar, J.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesGaspar, J. in OpenAIRE Grosjean, A.; Grosjean, A.
Harvested from ORCID Public Data FileGrosjean, A. in OpenAIRE Guillemaut, C.; Guirlet, R.; Gunn, J.P.; Hillairet, J.; Loarer, T.;Guillemaut, C.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesGuillemaut, C. in OpenAIRE Maget, P.; Manas, P.;Maget, P.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesMaget, P. in OpenAIRE Morales, J.; Pellissier, F.P.; Tsitrone, E.;Morales, J.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesMorales, J. in OpenAIRE Krieger, K.; Krieger, K.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesKrieger, K. in OpenAIRE Hakola, A.; Hakola, A.
Harvested from ORCID Public Data FileHakola, A. in OpenAIRE Widdowson, A.; Widdowson, A.
Derived by OpenAIRE algorithms or harvested from 3rd party repositoriesWiddowson, A. in OpenAIREFuture fusion reactors like ITER and DEMO will have all-tungsten (W) walls and long pulses. These features will make wall conditioning more difficult than in most of the existing devices. The W Environment Steady-state Tokamak (WEST) is one of the few long pulse (364 s) fusion devices with actively cooled W plasma-facing components in the world. WEST is a unique test bed to study impurity migration and plasma density control via reactor relevant wall conditioning techniques. The phase II of WEST operations began in 2022, after the installation of a new lower divertor, now entirely equipped with actively cooled, ITER grade, W monoblocks. After pump down, we baked WEST between 90 °C and 170 °C for ∼2 weeks. After 82.5 h at 90 °C and 33 h at 170 °C, vacuum conditions were stable with a vessel pressure of 6x10-5 Pa and mass spectra dominated by H2 molecules. While at 170 °C, we performed ∼40 h of D2 glow discharge cleaning (GDC) and ∼5 h of glow discharge boronization (GDB), using a 15 %-85 % B2D6-He mix and a total boron mass of ∼12 g. This was the very first GDB at such high temperature for WEST. The whole wall conditioning sequence led to a ∼10 times reduction of the H2O signal as well as to a ∼3 times reduction of the O2 signal, according to mass spectra. Once back to 70 °C, the vessel pressure was 5.5x10-6 Pa and plasma restart was seamless with ∼30 s cumulated over the very first 5 pulses and an Ohmic radiated power fraction Frad = 0.6, showing successful conditioning of the new ITER grade divertor. The effect of the first, ‘hot’ GDB faded with a characteristic cumulative injected energy of 2.45 GJ and saturation towards Frad ∼0.8. After 1.4 h and 7.5 GJ of cumulative plasma time and injected energy, we carried out a second GDB, this time at 70 °C. This ‘cold’ GDB initially led to a much lower Ohmic Frad = 0.3–0.4 but the effect lasted ∼7 times less, with a characteristic cumulative injected energy of 0.37 GJ. At the end of the campaign, we cumulated ∼3h and ∼30 GJ through repetitive, minute long pulses without any boronization. Throughout this 4-weeks-long experiment, Frad in the 4 MW heating phase evolved only marginally (from 0.5 to 0.55). This increase is mostly due to the build-up of re/co-deposited layers on both lower divertor targets.
Access RoutesGreen gold 6 citations 6 popularity Average influence Average impulse Top 10% Powered by BIP!add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
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You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2024.101741&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu - EC| EUROfusion ,EC| CAMART2 Paris, Peeter;
Paris, Peeter
Harvested from ORCID Public Data FileParis, Peeter in OpenAIRE Butikova, Jelena; Laan, Matti R.;Butikova, Jelena
Harvested from ORCID Public Data FileButikova, Jelena in OpenAIRE Hakola, A.; +5 AuthorsHakola, A.
Harvested from ORCID Public Data FileHakola, A. in OpenAIRE Paris, Peeter; Paris, Peeter
Harvested from ORCID Public Data FileParis, Peeter in OpenAIRE Butikova, Jelena; Laan, Matti R.;Butikova, Jelena
Harvested from ORCID Public Data FileButikova, Jelena in OpenAIRE Hakola, A.; Hakola, A.
Harvested from ORCID Public Data FileHakola, A. in OpenAIRE Jõgi, I.; Likonen, J.; Grigore, Eduard; Ruset; Cristian;ITER foresees applying laser induced breakdown spectroscopy (LIBS) as a tool for quantitative assessment of fuel retention in the first walls. One open problem related to LIBS application is the choice of the laser type. Here we compare two Nd/YAG lasers with different pulse durations, 0.15 and 8 ns, working at λ = 1064 nm for LIBS studies of samples with D-doped W/Al coatings of ≈ 3 μm thickness (Al is used as a proxy of Be) on Mo. Low pressure argon was used as a background gas. Experiments were done in conditions where other factors (broadening of spectral lines, signal-to-noise ratio, limited thickness of coatings etc.) did not shadow the effect of laser pulse duration. For these reasons, low pressure argon was used as the background gas and fluences were kept at comparatively low values. Spectra of laser-produced plasma were recorded as a function of the number of laser pulses. Partially overlapping lines of hydrogen isotopes were fitted with Voigt contours, intensities were fitted and depth profiles of deuterium were reconstructed. The relative standard error of curve-fitting of spectra recorded with the laser of shorter pulse duration was two times smaller than that recorded by the longer pulse laser. The electron density was found from the Stark broadening of Hα line of the laser-produced plasma and the electron temperature of plasma was found on the basis W and Mo lines. It was found that in the case of ps laser an acceptable accuracy of the detection of deuterium was possible at considerably lower values of fluence. Steps needed for comparison of ps and ns lasers in ITER-relevant conditions were discussed.
Access RoutesGreen gold 21 citations 21 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2018.11.018&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu - EC| EUROfusion ,EC| CAMART2 Paris, Peeter;
Paris, Peeter
Harvested from ORCID Public Data FileParis, Peeter in OpenAIRE Butikova, Jelena; Laan, Matti R.;Butikova, Jelena
Harvested from ORCID Public Data FileButikova, Jelena in OpenAIRE Hakola, A.; +5 AuthorsHakola, A.
Harvested from ORCID Public Data FileHakola, A. in OpenAIRE Paris, Peeter; Paris, Peeter
Harvested from ORCID Public Data FileParis, Peeter in OpenAIRE Butikova, Jelena; Laan, Matti R.;Butikova, Jelena
Harvested from ORCID Public Data FileButikova, Jelena in OpenAIRE Hakola, A.; Hakola, A.
Harvested from ORCID Public Data FileHakola, A. in OpenAIRE Jõgi, I.; Likonen, J.; Grigore, Eduard; Ruset; Cristian;ITER foresees applying laser induced breakdown spectroscopy (LIBS) as a tool for quantitative assessment of fuel retention in the first walls. One open problem related to LIBS application is the choice of the laser type. Here we compare two Nd/YAG lasers with different pulse durations, 0.15 and 8 ns, working at λ = 1064 nm for LIBS studies of samples with D-doped W/Al coatings of ≈ 3 μm thickness (Al is used as a proxy of Be) on Mo. Low pressure argon was used as a background gas. Experiments were done in conditions where other factors (broadening of spectral lines, signal-to-noise ratio, limited thickness of coatings etc.) did not shadow the effect of laser pulse duration. For these reasons, low pressure argon was used as the background gas and fluences were kept at comparatively low values. Spectra of laser-produced plasma were recorded as a function of the number of laser pulses. Partially overlapping lines of hydrogen isotopes were fitted with Voigt contours, intensities were fitted and depth profiles of deuterium were reconstructed. The relative standard error of curve-fitting of spectra recorded with the laser of shorter pulse duration was two times smaller than that recorded by the longer pulse laser. The electron density was found from the Stark broadening of Hα line of the laser-produced plasma and the electron temperature of plasma was found on the basis W and Mo lines. It was found that in the case of ps laser an acceptable accuracy of the detection of deuterium was possible at considerably lower values of fluence. Steps needed for comparison of ps and ns lasers in ITER-relevant conditions were discussed.
Access RoutesGreen gold 21 citations 21 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.<script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://beta.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1016/j.nme.2018.11.018&type=result"></script>'); --> </script>For further information contact us at helpdesk@openaire.eu
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