Plasma Interactions with Mixed Materials and Impurity Transport

Technical Report · Fri Oct 28 04:00:00 EDT 2016

DOI:https://doi.org/10.2172/1332472· OSTI ID:1332472

Rognlien, T. D. ^[1]; Beiersdorfer, Peter ^[1]; Chernov, A. ^[1]; Frolov, T. ^[1]; Magee, E. ^[1]; Rudd, R. ^[1]; Umansky, M. ^[1]

---

1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

The project brings together three discipline areas at LLNL to develop advanced capability to predict the impact of plasma/material interactions (PMI) on metallic surfaces in magnetic fusion energy (MFE) devices. These areas are (1) modeling transport of wall impurity ions through the edge plasma to the core plasma, (2) construction of a laser blow-off (LBO) system for injecting precise amounts of metallic atoms into a tokamak plasma, and (3) material science analysis of fundamental processes that modify metallic surfaces during plasma bombardment. The focus is on tungsten (W), which is being used for the ITER divertor and in designs of future MFE devices. In area (1), we have worked with the University of California, San Diego (UCSD) on applications of the UEDGE/DUSTT coupled codes to predict the influx of impurity ions from W dust through the edge plasma, including periodic edge-plasma oscillations, and revived a parallel version of UEDGE to speed up these simulations. In addition, the impurity transport model in the 2D UEDGE code has been implemented into the 3D BOUT++ turbulence/transport code to allow fundamental analysis of the impact of strong plasma turbulence on the impurity transport. In area (2), construction and testing of the LBO injection system has been completed. The original plan to install the LBO on the National Spherical Torus Experiment Upgrade (NSTX-U) at Princeton and its use to validate the impurity transport simulations is delayed owing to NSTX-U being offline for substantial magnetic coil repair period. In area (3), an analytic model has been developed to explain the growth of W tendrils (or fuzz) observed for helium-containing plasmas. Molecular dynamics calculations of W sputtering by W and deuterium (D) ions shows that a spatial blending of interatomic potentials is needed to describe the near-surface and deeper regions of the material.

• Research Organization: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
• Sponsoring Organization: USDOE Laboratory Directed Research and Development (LDRD) Program
• DOE Contract Number: AC52-07NA27344
• OSTI ID: 1332472
• Report Number(s): LLNL-TR--707266
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
COMPUTERIZED SIMULATION
DESIGN
DEUTERIUM
DIVERTORS
DUSTS
HELIUM
IMPURITIES
INTERATOMIC FORCES
IONS
LASER RADIATION
MOLECULAR DYNAMICS METHOD
NEUTRAL ATOM BEAM INJECTION
NSTX DEVICE
PERIODICITY
PLASMA WAVES
POTENTIALS
SPUTTERING
SURFACES
TESTING
TRANSPORT THEORY
TUNGSTEN
TURBULENCE
U CODES
WALL EFFECTS