Technical Meeting on the Collisional-Radiative Properties of Tungsten and Hydrogen in Edge Plasma of Fusion Devices

This meeting was held to evaluate and recommend fundamental data concerning tungsten, hydrogen, their ions and molecules in the edge plasma region of experimental nuclear fusion devices with a view to quantifying and reducing the uncertainties in the modelling of its collisional, radiative and plasma-material interaction properties.

The meeting was held virtually, from 29 March – 1 April 2021. More details, including abstract and presentation materials upload, are available on the IAEA conferences page (login required). The Scientific Secretary is Kalle HEINOLA.

Organizing Committee

  • Ursel FANTZ (University of Augsburg, Germany)
  • Kalle HEINOLA (IAEA)
  • Christian HILL (IAEA)
  • Sebastiján BREZINSEK (Forschungszentrum Jülich, Germany)

Sessions

A. Experiments: Tokamaks, Linear Plasmas, Stellarators

Experimental devices: JET (attached/detached), AUG, DIII-D, MAGNUM, PSI-2, ITER , JT60-SA, T10

  • Metallic vs. graphite surfaces
  • Isotope experiments
  • Reflection and recycling
  • Surface conditions and processes
  • Spectroscopy and other methods
B. Modelling: Tokamaks, Linear Plasmas, Stellarators

Codes: SOLPS-ITER, EMC3-EIRENE, SONIC NEUT2D, EDGE2D-EIRENE, TOKAM3-X, SOLEDGE-EIRENE

  • Issues with benchmarks
  • Attached and detached conditions
  • Isotope effects
  • Spectroscopy
  • Neutral pressure benchmarks
C. Experiments: Atomic and Molecular Data, Cross Sections, Processes
  • Isotope effects
  • Rotationally and vibrationally-resolved spectroscopy
  • Highly-excited species
  • Mixed molecules
  • Other hydrogen-containing molecules
  • Spectroscopy tools
D. Modelling: Atomic and Molecular Data calculations
  • Convergent-close coupling methods
  • High-temperature molecular spectroscopic line lists
E. Collisional Radiative Models

Codes: YACORA, EIRENE, EUMONIA, NEUT2D

  • Outcome of EU-ADAS for molecules
  • Vibrationally resolved CR
  • Time dependent methods
  • Application to detached conditions
F. Needs and Conclusions
  • Publications
  • Potential CRP

Topics

Recombination rate coefficients for Wq+: experiments and theory

Existing experimental recombination rate coefficients and cross sections are known for electron energies up to several hundred eV (i.e. for W18+ – 21+ ). However, at low energies the total recombination cross sections are orders of magnitude above those for radiative recombination. EBITS can be used for obtaining recombination cross sections, but energies below about 20 eV are not accessible experimentally, and this is the region with largest theoretical uncertainty.

The role of external electromagnetic fields on dielectronic recombination: high fields may have a large effect on plasma rate coefficients. For example, in Fe15+ the dielectronic recombination can change by a factor of 3 at temperatures of 105 to 106 K and at an electric field strength of kV/cm.

Electron-impact ionization of Wq+

The effect of long-lived states: experimental electron-impact ionization cross sections for W1+ – 19+ with energies up to 1 keV exist. However, in the experiments even if the multiply-charged ions are stored for some time, the effect of long-lived excited states (in the parent ion beam) will be present in the cross section measurements. Fine energy scans and good statistics can reveal these metastable ions. Theoretical modelling of the resulting cross sections can provide information on the long-lived beam components. Fusion plasma will contain such species in long-lived excited states whose cross sections are needed.

Resonant processes in high charge states and their contribution to net ionization: it is necessary to explore which charge states of W might have resonant contributions and to assess the related cross sections (modelling with, for example, R-matrix methods may be necessary as experiments are challenging).

Electron-impact excitation of Wq+

There is a lack of experimental data for electron-impact excitations in W.

Charge-transfer collisions of Wq+ with plasma species

Particular species of interest are: H/D/T, He and He+. The cross sections are well known in general, but at very low energies their uncertainties are unquantified. As with electron-collision experiments involving multiply charged W, the role of metastable states is largely unknown.

Spectroscopic issues in the divertor region

Non-LTE modelling: near the divertor the electron density is higher and the temperature lower than in main plasma, but due to divertor conditions non-LTE modelling may be required: emission data are needed for W erosion assessments (maximum charge states anticipated are W6+ – 8+; excluding transient events, are higher charge states expected?) No reliable NLTE modelling exists for W0 – 5+.

Re-assessment of the role of MAR in tungsten machines: Molecular Assisted Recombination (MAR) can play an important role in assisting the volume recombination (by three-body and radiative recombination of atomic ions) in detached divertor plasma. Detailed investigations of MAR were done almost two decades ago, but on machines using carbon as a plasma-facing material. The properties of carbon and tungsten with respect to their interaction with hydrogen (i.e. the probability of H2 formation at their surfaces) are very different; therefore, the role of MAR in modern fusion devices may differ from that determined for carbon machines.

Tungsten charge state distributions: plasma transport may shape the W charge state distribution (CSD): transport effects may change the averaged charge density <Z> and broaden the spatial range. The CSD deviates from transport-free, equilibrium values and offers information on plasma transport, provided that adequate ionization balance calculations are available. This is crucial for ITER: plasma transport measurements focus on the ionization balance of W. In ITER there will be no low-Z neutral beams employed, which are used in other fusion devices to monitor and observe plasma transport.

Atomic and molecular data: theory and modelling

Collisional-Radiative (CR) modelling: the relation of CR modelling to plasma transport simulations; non-LTE code activities on testing CR codes for W; CR model implementations: configurational average (i.e. <Z>) vs. detailed models (up to thousands of charge states).

Molecular radiation of hydrogen and deuterium (OES and UV/VUV ranges): Detecting and interpreting molecular radiation gives access to molecular fluxes as well as vibrational and rotational populations: parameters that are of relevance to assessing the effectiveness of MAR (see above), The accuracy of modelling molecular radiation by collisional-radiative models is directly correlated with the accuracy and completeness of the set of input data used, including the cross sections for electron-impact excitation of molecular states. Up to now, two strongly-diverging sets of cross sections were available; the first steps towards establishing a more reliable and accurate alternative set are currently in progress.

The effect of opacity

Self-absorption caused by optical thickness of the atomic Lyman emission lines can result in significant radiation trapping, influencing the energy balance and the ionization / recombination rates in the divertor plasma. If the radiation trapping is high, this may make the transition to a detached divertor more difficult. A second effect of opacity is that it strongly affects the intensity of emission lines and has to be taken into account in population models used for interpreting such emission. To do so, profiles of the opacity along the line-of-sight used are needed; this information is not presently available.

Middle-charge states of W (W10+ – 25+)

In ITER medium charge states of W are expected to be responsible for the majority of re-radiation from transient pulses. Key processes for which data is needed are: ion line data and ionization, recombination and excitation rates.

Related Projects and Meetings

Agenda

Monday, 29 March 2021

09:00 – 09:30Meeting opening, welcome, introductions
Session 1: EXP/1-1 Experiments: Tokamaks, Linear Plasmas, Stellarators

Chair: Sebastiján BREZINSEK

09:30 – 10:00Sebastiján BREZINSEK (Forschungszentrum Jülich (FZJ), Germany)
Hydrogen recycling and Tungsten sources in fusion-relevant edge plasmas: spectroscopy in PSI-2 and JET
[presentation (pdf: 6.8 MB)]
10:00 – 10:30Motoshi GOTO (National Institute for Fusion Science, Japan)
Spectroscopic studies for tungsten and hydrogen in LHD
[abstract (pdf: 40.7 KB)] [presentation (pdf: 12.9 MB)]
10:30 – 10:45Coffee Break
Session 2: MOD/1-1 Modelling: Tokamaks, Linear Plasmas, Stellarators

Chair: Sven WIESEN

10:45 – 11:15Xavier BONNIN (ITER, France)
Tungsten atomic data needs for ITER
[abstract (pdf: 29.6 KB)] [presentation (pdf: 1.1 MB)]
11:15 – 11:45Sven WIESEN (Forschungszentrum Jülich (FZJ), Germany)
Application of Monte-Carlo methods for photon transport in divertors
[abstract (pdf: 32.6 KB)] [presentation (pdf: 5.0 MB)]
11:45 – 12:15Discussion
12:15 – 12:45Lunch
Session 3: EXP/1-2 Experiments: Tokamaks, Linear Plasmas, Stellarators

Chair: Sebastiján BREZINSEK

12:45 – 13:15Richard ENGELN (Eindhoven University of Technology, Netherlands)
Reaction dynamics in a magnetized hydrogen plasma unraveled by optical spectroscopic techniques
[abstract (pdf: 41.2 KB)] [presentation (pdf: 7.0 MB)]
13:15 – 13:45Alexander ZIMIN (Bauman Moscow State Technical University, Russia)
Digital Atlas of Electronic Vibrational-Rotational Transitions in Deuterium and Protium Molecules [WITHDRAWN]
13:45 – 14:15Ivo CLASSEN (Dutch Institute for Fundamental Energy Research (DIFFER), Netherlands)
Investigating the role of neutral particles in the linear device Magnum-PSI
[abstract (pdf: 34.3 KB)] [presentation (pdf: 9.9 MB)]
14:15 – 14:30Coffee Break
Session 4: MOD/1-2 Modelling: Tokamaks, Linear Plasmas, Stellarators

Chair: Sven WIESEN

14:30 – 15:00Mathias GROTH (Aalto University, Finland)
Hydrogenic atomic and molecular emission measurements in JET-ILW for assessing the role of ion-molecular interaction in divertor detachment
[abstract (pdf: 37.6 KB)] [presentation (pdf: 142.5 KB)]
15:00 – 15:30Kevin VERHAEGH (Culham Centre for Fusion Energy, United Kingdom)
An experimental analysis of the impact of plasma-molecule interactions on particle losses, atomic line emission and resulting power losses
[abstract (pdf: 40.4 KB)] [presentation (pdf: 3.2 MB)]
15:30 – 16:30Discussion

Tuesday, 30 March 2021

Session 5: EXP/1-3 Experiments: Tokamaks, Linear Plasmas, Stellarators

Chair: Sebastiján BREZINSEK

09:00 – 09:30Ewa PAWELEC (University of Opole, Poland)
Measurements of the W concentration in the low- and mid-temperature range
[abstract (pdf: 36.2 KB)] [presentation (pdf: 1.2 MB)]
09:30 – 10:00Rudolf NEU (Technical University of Munich, Germany)
Spectroscopic Diagnostic of Tungsten at ASDEX Upgrade
[abstract (pdf: 34.9 KB)] [presentation (pdf: 109.0 KB)]
10:00 – 10:15Coffee Break
Session 6: CR/1 Collisional Radiative Models

Chairs: Ursel FANTZ and Dirk WÜNDERLICH

10:15 – 10:45Dirk WÜNDERLICH (Max Planck Institute for Plasma Physics, Garching, Germany)
Collisional radiative models for atomic and molecular hydrogen in the edge plasma of fusion devices
[abstract (pdf: 33.7 KB)] [presentation (pdf: 1.1 MB)]
10:45 – 11:15Annarita LARICCHIUTA (CNR Bari, Italy)
State-to-state self-consistent kinetic modelling of hydrogen plasmas
[abstract (pdf: 39.1 KB)] [presentation (pdf: 6.8 MB)]
11:15 – 11:45Discussion
11:45 – 12:15Lunch
Session 7: CR/1 Collisional Radiative Models

Chairs: Ursel FANTZ and Dirk WÜNDERLICH

12:15 – 12:45Connor BALLANCE (Queen's University Belfast, United Kingdom)
Electron-impact excitation and ionisation R-matrix calculations in support of Tungsten tokamak diagnostics
[abstract (pdf: 32.3 KB)] [presentation (pdf: 1.7 MB)]
12:45 – 13:15Kerry LAWSON (Culham Centre for Fusion Energy, United Kingdom)
He II as a proxy for D I
[abstract (pdf: 36.2 KB)] [presentation (pdf: 4.9 MB)]
13:15 – 13:30Virtual Coffee Break
Session 8: MOD/2-1 Modelling: Atomic and Molecular Data calculations

Chair: Martin O'MULLANE

13:30 – 14:00Martin O'MULLANE (Department of Physics, University of Strathclyde, United Kingdom)
Fundamental atomic data for tungsten and hydrogen and the effect of the finite density edge plasma
[abstract (pdf: 30.9 KB)] [presentation (pdf: 2.1 MB)]
14:00 – 14:30Alain DUBOIS (Laboratoire de Chimie Physique – Matière et Rayonnement (LCPMR), Sorbonne Université, France)
Production of cross sections for atomic collisions with Asymptotic Orbital Semiclassical Coupled Channel calculations
[abstract (pdf: 32.3 KB)]
14:30 – 14:45Virtual Coffee Break
14:45 – 15:45Discussion

Wednesday, 31 March 2021

Session 9: MOD/2-3 Modelling: Atomic and Molecular Data calculations

Chair: Martin O'MULLANE

09:00 – 09:30Dmitry FURSA (Faculty of Science and Engineering, Curtin University, Australia)
Complete collision data set for electrons scattering on molecular hydrogen and its isotopologues
[abstract (pdf: 43.1 KB)] [presentation (pdf: 5.6 MB)]
09:30 – 10:00Vincenzo LAPORTA (CNR Bari, Italy)
Vibrational excitation and dissociation of deuterium molecule by electron impact
[abstract (pdf: 514.6 KB)] [presentation (pdf: 5.0 MB)]
10:00 – 10:30Ioan F. SCHNEIDER (Université du Havre, France)
Electron collisions with H2+, HD+ and D2+: computation of cross sections and rate coefficients, and comparison with storage ring measurements
[abstract (pdf: 36.4 KB)] [presentation (pdf: 19.0 MB)]
Session 10: EXP/2-1 Experiments: Atomic and Molecular Data, Cross Sections, Processes

Chair: Sebastiján BREZINSEK

10:30 – 10:45Virtual Coffee Break
10:45 – 11:15Baoren WEI (Fudan University, China)
Charge Exchange Cross Section Measurement at Fudan University
[abstract (pdf: 34.8 KB)] [presentation (pdf: 5.7 MB)]
11:15 – 11:45Stephan ERTMER (Forschungszentrum Jülich (FZJ), Germany)
Spectroscopic investigations on energy, angular and atomic level distribution functions of sputtered tungsten
[abstract (pdf: 43.6 KB)] [presentation (pdf: 6.1 MB)]
11:45 – 12:15Discussion
12:15 – 12:45Lunch
Session 11: MOD/1-3 Modelling: Tokamaks, Linear Plasmas, Stellarators

Chair: Sven WIESEN

12:45 – 13:15David TSKHAKAYA (Institute of Plasma Physics of the Czech Academy of Sciences, Czechia)
Needs of atomic data for kinetic modelling of fusion plasma edge
[abstract (pdf: 32.0 KB)] [presentation (pdf: 3.5 MB)]
13:15 – 13:45Jerome GUTERL (General Atomics, United States of America)
Theoretical analysis and experimental validation in DIII-D of predictive modeling for tungsten erosion and redeposition in tokamak divertors
[abstract (pdf: 34.6 KB)] [presentation (pdf: 6.0 MB)]
13:45 – 14:15Andreas KIRSCHNER (Forschungszentrum Jülich (FZJ), Germany)
Atomic data needs for tungsten erosion, migration and deposition modelling in fusion devices
[abstract (pdf: 33.7 KB)]
14:15 – 14:30Coffee Break
14:30 – 15:30Discussion: Special session for MOD/1 fusion devices
15:30 – 16:30Discussion (all participants)

Thursday, 1 April 2021

Session 12: Meeting Summary
09:00 – 09:30Session A Summary: Experiments: Tokamaks, Linear Plasmas, Stellarators
09:30 – 10:00Session B Summary: Modelling: Tokamaks, Linear Plasmas, Stellarators
10:00 – 10:30Session C Summary: Experiments: Atomic and Molecular Data, Cross Sections, Processes
10:30 – 10:45Coffee Break
10:45 – 11:15Session D Summary: Modelling: Atomic and Molecular Data calculations
11:15 – 11:45Session E Summary: Collisional Radiative Models
11:45 – 12:45Discussion; Meeting adjournment

Participants

39 participants from 14 countries.

Connor BALLANCE Queen's University Belfast, United Kingdom
Xavier BONNIN ITER, France
Sebastiján BREZINSEK Forschungszentrum Jülich (FZJ), Germany
Ivo CLASSEN Dutch Institute for Fundamental Energy Research (DIFFER), Netherlands
Alain DUBOIS Laboratoire de Chimie Physique – Matière et Rayonnement (LCPMR), Sorbonne Université, France
Richard ENGELN Eindhoven University of Technology, Netherlands
Stephan ERTMER Forschungszentrum Jülich (FZJ), Germany
Dmitry FURSA Faculty of Science and Engineering, Curtin University, Australia
Motoshi GOTO National Institute for Fusion Science, Japan
Mathias GROTH Aalto University, Finland
Jerome GUTERL General Atomics, United States of America
Andreas KIRSCHNER Forschungszentrum Jülich (FZJ), Germany
Vincenzo LAPORTA CNR Bari, Italy
Annarita LARICCHIUTA CNR Bari, Italy
Kerry LAWSON Culham Centre for Fusion Energy, United Kingdom
Rudolf NEU Technical University of Munich, Germany
Martin O'MULLANE Department of Physics, University of Strathclyde, United Kingdom
Ewa PAWELEC University of Opole, Poland
Ioan F. SCHNEIDER Université du Havre, France
David TSKHAKAYA Institute of Plasma Physics of the Czech Academy of Sciences, Czechia
Kevin VERHAEGH Culham Centre for Fusion Energy, United Kingdom
Baoren WEI Fudan University, China
Sven WIESEN Forschungszentrum Jülich (FZJ), Germany
Dirk WÜNDERLICH Max Planck Institute for Plasma Physics, Garching, Germany
Alexander ZIMIN Bauman Moscow State Technical University, Russia
Christian HILL IAEA
Kalle HEINOLA IAEA
Ursel FANTZ Max Planck Institute for Plasma Physics, Garching, Germany
Bowen LI Lanzhou School of Nuclear Science and Technology, China
Yong WU Institute of Applied Physics and Computational Mathematics (IAPCM), China
Hennie VAN DER MEIDEN Dutch Institute for Fundamental Energy Research (DIFFER), Netherlands
Dmitriy BORODIN Forschungszentrum Jülich (FZJ), Germany
Man MOHAN University of Delhi, India
Jonathan TENNYSON University College London, United Kingdom
Marco WISCHMEIER Max Planck Institute for Plasma Physics, Garching, Germany
Sk. Musharaf ALI Bhabha Atomic Research Centre, India
Derek HARTING Forschungszentrum Jülich (FZJ), Germany
Thierry KREMEYER University of Wisconsin-Madison, United States of America
David COSTER Max Planck Institute for Plasma Physics, Garching, Germany

Presentations

Connor BALLANCE (Queen's University Belfast, United Kingdom)
Electron-impact excitation and ionisation R-matrix calculations in support of Tungsten tokamak diagnostics
[abstract (pdf: 32.3 KB)] [presentation (pdf: 1.7 MB)]

Xavier BONNIN (ITER, France)
Tungsten atomic data needs for ITER
[abstract (pdf: 29.6 KB)] [presentation (pdf: 1.1 MB)]

Sebastiján BREZINSEK (Forschungszentrum Jülich (FZJ), Germany)
Hydrogen recycling and Tungsten sources in fusion-relevant edge plasmas: spectroscopy in PSI-2 and JET
[presentation (pdf: 6.8 MB)]

Ivo CLASSEN (Dutch Institute for Fundamental Energy Research (DIFFER), Netherlands)
Investigating the role of neutral particles in the linear device Magnum-PSI
[abstract (pdf: 34.3 KB)] [presentation (pdf: 9.9 MB)]

Alain DUBOIS (Laboratoire de Chimie Physique – Matière et Rayonnement (LCPMR), Sorbonne Université, France)
Production of cross sections for atomic collisions with Asymptotic Orbital Semiclassical Coupled Channel calculations
[abstract (pdf: 32.3 KB)]

Richard ENGELN (Eindhoven University of Technology, Netherlands)
Reaction dynamics in a magnetized hydrogen plasma unraveled by optical spectroscopic techniques
[abstract (pdf: 41.2 KB)] [presentation (pdf: 7.0 MB)]

Stephan ERTMER (Forschungszentrum Jülich (FZJ), Germany)
Spectroscopic investigations on energy, angular and atomic level distribution functions of sputtered tungsten
[abstract (pdf: 43.6 KB)] [presentation (pdf: 6.1 MB)]

Dmitry FURSA (Faculty of Science and Engineering, Curtin University, Australia)
Complete collision data set for electrons scattering on molecular hydrogen and its isotopologues
[abstract (pdf: 43.1 KB)] [presentation (pdf: 5.6 MB)]

Motoshi GOTO (National Institute for Fusion Science, Japan)
Spectroscopic studies for tungsten and hydrogen in LHD
[abstract (pdf: 40.7 KB)] [presentation (pdf: 12.9 MB)]

Mathias GROTH (Aalto University, Finland)
Hydrogenic atomic and molecular emission measurements in JET-ILW for assessing the role of ion-molecular interaction in divertor detachment
[abstract (pdf: 37.6 KB)] [presentation (pdf: 142.5 KB)]

Jerome GUTERL (General Atomics, United States of America)
Theoretical analysis and experimental validation in DIII-D of predictive modeling for tungsten erosion and redeposition in tokamak divertors
[abstract (pdf: 34.6 KB)] [presentation (pdf: 6.0 MB)]

Andreas KIRSCHNER (Forschungszentrum Jülich (FZJ), Germany)
Atomic data needs for tungsten erosion, migration and deposition modelling in fusion devices
[abstract (pdf: 33.7 KB)]

Vincenzo LAPORTA (CNR Bari, Italy)
Vibrational excitation and dissociation of deuterium molecule by electron impact
[abstract (pdf: 514.6 KB)] [presentation (pdf: 5.0 MB)]

Annarita LARICCHIUTA (CNR Bari, Italy)
State-to-state self-consistent kinetic modelling of hydrogen plasmas
[abstract (pdf: 39.1 KB)] [presentation (pdf: 6.8 MB)]

Kerry LAWSON (Culham Centre for Fusion Energy, United Kingdom)
He II as a proxy for D I
[abstract (pdf: 36.2 KB)] [presentation (pdf: 4.9 MB)]

Rudolf NEU (Technical University of Munich, Germany)
Spectroscopic Diagnostic of Tungsten at ASDEX Upgrade
[abstract (pdf: 34.9 KB)] [presentation (pdf: 109.0 KB)]

Martin O'MULLANE (Department of Physics, University of Strathclyde, United Kingdom)
Fundamental atomic data for tungsten and hydrogen and the effect of the finite density edge plasma
[abstract (pdf: 30.9 KB)] [presentation (pdf: 2.1 MB)]

Ewa PAWELEC (University of Opole, Poland)
Measurements of the W concentration in the low- and mid-temperature range
[abstract (pdf: 36.2 KB)] [presentation (pdf: 1.2 MB)]

Ioan F. SCHNEIDER (Université du Havre, France)
Electron collisions with H2+, HD+ and D2+: computation of cross sections and rate coefficients, and comparison with storage ring measurements
[abstract (pdf: 36.4 KB)] [presentation (pdf: 19.0 MB)]

David TSKHAKAYA (Institute of Plasma Physics of the Czech Academy of Sciences, Czechia)
Needs of atomic data for kinetic modelling of fusion plasma edge
[abstract (pdf: 32.0 KB)] [presentation (pdf: 3.5 MB)]

Kevin VERHAEGH (Culham Centre for Fusion Energy, United Kingdom)
An experimental analysis of the impact of plasma-molecule interactions on particle losses, atomic line emission and resulting power losses
[abstract (pdf: 40.4 KB)] [presentation (pdf: 3.2 MB)]

Baoren WEI (Fudan University, China)
Charge Exchange Cross Section Measurement at Fudan University
[abstract (pdf: 34.8 KB)] [presentation (pdf: 5.7 MB)]

Sven WIESEN (Forschungszentrum Jülich (FZJ), Germany)
Application of Monte-Carlo methods for photon transport in divertors
[abstract (pdf: 32.6 KB)] [presentation (pdf: 5.0 MB)]

Dirk WÜNDERLICH (Max Planck Institute for Plasma Physics, Garching, Germany)
Collisional radiative models for atomic and molecular hydrogen in the edge plasma of fusion devices
[abstract (pdf: 33.7 KB)] [presentation (pdf: 1.1 MB)]

Alexander ZIMIN (Bauman Moscow State Technical University, Russia)
Digital Atlas of Electronic Vibrational-Rotational Transitions in Deuterium and Protium Molecules