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Title: Quantum-Classical Science for the Plasma-Material Interface in NSTXU - Final Technical Report

Abstract

Plasma facing surfaces (PFS) have a profound influence on plasma performance and choice of material for PFSs is a burning issue for tokamak reactors. Using lithium wall conditioning in NSTX has resulted in a beneficial influence on plasma behavior including control of hydrogen recycling and improvements in energy confinement, longer confinement times, edge density control, and the elimination of Edge Localized Modes. A major challenge for the NSTX-U (increased power flux, increased campaign time) as well as for other magnetic fusion devices is to extend high-performance plasmas for very long durations, and to integrate this high performance with plasma facing components (PFCs) that can withstand very high heat and particle fluxes while maintaining structural integrity with minimal retention of fusion fuel. This project directly contributed to filling up the knowledge gaps and data for the dynamics of the plasma-facing interfaces in the NSTX-U at nano and nano-to-micro scales. This was achieved by both deciphering the poorly understood nanoscale phenomenology of plasma-surface interactions and providing the connection and comparison with the experiments which provide understanding at the mesoscopic scales. We modelled the dynamic response and evolution of a mixed material surfaces (D, Li, C, B, O) to bombardment by plasma particles,more » and investigated microstructure changes, erosion, surface chemistry, deuterium implantation and permeation. The main objectives of the project are i) a comparison of Li and B effects when deposited on carbon, and ii) the role of oxygen and other impurities (e.g. carbon, boron) in the lithium performance. In addition to predicting and understanding the phenomenology of the processes, the project achieved deliverables on the i) plasma induced erosion rates of PFCs (outer wall, divertor, etc.), including chemical and physical sputtering yields at various temperatures (300-700K), ii) deuterium uptake/recycling rates, and iii) accurate probability rates for the processes and reactions in i-ii which were used to understand the experimental results of the J.P. Allain and B. Koel NSTX-U projects. Lithium was a distinctive focus of the project. It easily charges in contact with other fusion material atoms, giving partially or fully its external electron cloud to other atoms in its vicinity and polarizing the mixed material. Our research strategy used experimentally validated multiscale theory applied to the large, multicomponent material surface systems. With the use of US supercomputing facilities we simulated evolution of atomic charges, chemistry, retention of deuterium, sputtering and morphology by introducing the corrections to the classical molecular dynamics, like are electronegativity equalization method (EEM) and quantum-classical molecular dynamics (QCMD). The goal was to understand and quantify the dynamics of the creation and evolution of the plasma-material interface under irradiation by atoms and molecules at boronized carbon, lithiated carbon, and boronized-lithiated carbon for both solid and self-healing liquid-metal divertor.« less

Authors:
 [1];  [2];  [3];  [4];  [5]
  1. Max Planck Inst, Harching, Germany; Srony Brook university
  2. Stony Brook University
  3. University of Illinois at Urbana-Champaign
  4. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); University of Illinois at Urbana, Champaign
  5. Princeton Univ., NJ (United States)
Publication Date:
Research Org.:
The Research Foundation of State University of New York in Stony Brook, Stony Brook, NY 117943362
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
Contributing Org.:
Princeton Plasma Physics Laboratory University of Illinois at Urbana-Champaign
OSTI Identifier:
1567016
Report Number(s):
DE-SC0013752-1
CFDS 81.049
DOE Contract Number:  
SC0013752
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 36 MATERIALS SCIENCE; 74 ATOMIC AND MOLECULAR PHYSICS; magnetic fusion, molecular dynamics, plasma-surface interactions, NSTX-U, quantum, classical, lithium, boron, oxygen, carbon, sputtering, retention

Citation Formats

Dominguez, Francisco Javier, Krstic, Predrag, Allain, Jean Paul, Bedoya, Felipe, and Koel, Bruce. Quantum-Classical Science for the Plasma-Material Interface in NSTXU - Final Technical Report. United States: N. p., 2019. Web. doi:10.2172/1567016.
Dominguez, Francisco Javier, Krstic, Predrag, Allain, Jean Paul, Bedoya, Felipe, & Koel, Bruce. Quantum-Classical Science for the Plasma-Material Interface in NSTXU - Final Technical Report. United States. https://doi.org/10.2172/1567016
Dominguez, Francisco Javier, Krstic, Predrag, Allain, Jean Paul, Bedoya, Felipe, and Koel, Bruce. Sat . "Quantum-Classical Science for the Plasma-Material Interface in NSTXU - Final Technical Report". United States. https://doi.org/10.2172/1567016. https://www.osti.gov/servlets/purl/1567016.
@article{osti_1567016,
title = {Quantum-Classical Science for the Plasma-Material Interface in NSTXU - Final Technical Report},
author = {Dominguez, Francisco Javier and Krstic, Predrag and Allain, Jean Paul and Bedoya, Felipe and Koel, Bruce},
abstractNote = {Plasma facing surfaces (PFS) have a profound influence on plasma performance and choice of material for PFSs is a burning issue for tokamak reactors. Using lithium wall conditioning in NSTX has resulted in a beneficial influence on plasma behavior including control of hydrogen recycling and improvements in energy confinement, longer confinement times, edge density control, and the elimination of Edge Localized Modes. A major challenge for the NSTX-U (increased power flux, increased campaign time) as well as for other magnetic fusion devices is to extend high-performance plasmas for very long durations, and to integrate this high performance with plasma facing components (PFCs) that can withstand very high heat and particle fluxes while maintaining structural integrity with minimal retention of fusion fuel. This project directly contributed to filling up the knowledge gaps and data for the dynamics of the plasma-facing interfaces in the NSTX-U at nano and nano-to-micro scales. This was achieved by both deciphering the poorly understood nanoscale phenomenology of plasma-surface interactions and providing the connection and comparison with the experiments which provide understanding at the mesoscopic scales. We modelled the dynamic response and evolution of a mixed material surfaces (D, Li, C, B, O) to bombardment by plasma particles, and investigated microstructure changes, erosion, surface chemistry, deuterium implantation and permeation. The main objectives of the project are i) a comparison of Li and B effects when deposited on carbon, and ii) the role of oxygen and other impurities (e.g. carbon, boron) in the lithium performance. In addition to predicting and understanding the phenomenology of the processes, the project achieved deliverables on the i) plasma induced erosion rates of PFCs (outer wall, divertor, etc.), including chemical and physical sputtering yields at various temperatures (300-700K), ii) deuterium uptake/recycling rates, and iii) accurate probability rates for the processes and reactions in i-ii which were used to understand the experimental results of the J.P. Allain and B. Koel NSTX-U projects. Lithium was a distinctive focus of the project. It easily charges in contact with other fusion material atoms, giving partially or fully its external electron cloud to other atoms in its vicinity and polarizing the mixed material. Our research strategy used experimentally validated multiscale theory applied to the large, multicomponent material surface systems. With the use of US supercomputing facilities we simulated evolution of atomic charges, chemistry, retention of deuterium, sputtering and morphology by introducing the corrections to the classical molecular dynamics, like are electronegativity equalization method (EEM) and quantum-classical molecular dynamics (QCMD). The goal was to understand and quantify the dynamics of the creation and evolution of the plasma-material interface under irradiation by atoms and molecules at boronized carbon, lithiated carbon, and boronized-lithiated carbon for both solid and self-healing liquid-metal divertor.},
doi = {10.2172/1567016},
url = {https://www.osti.gov/biblio/1567016}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {9}
}