Toroidally symmetric plasma vortex at tokamak divertor null point

Journal Article · 08 March 2016 · Physics of Plasmas

DOI: https://doi.org/10.1063/1.4943101 · OSTI ID:1368023

Umansky, M. V. ^[1]; Ryutov, D. D. ^[1]

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

Reduced MHD equations are used for studying toroidally symmetric plasma dynamics near the divertor null point. Numerical solution of these equations exhibits a plasma vortex localized at the null point with the time-evolution defined by interplay of the curvature drive, magnetic restoring force, and dissipation. Convective motion is easier to achieve for a second-order null (snowflake) divertor than for a regular x-point configuration, and the size of the convection zone in a snowflake configuration grows with plasma pressure at the null point. In conclusion, the trends in simulations are consistent with tokamak experiments which indicate the presence of enhanced transport at the null point.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC52-07NA27344
• OSTI ID: 1368023
• Alternate ID(s): OSTI ID: 1241397
• Report Number(s): LLNL-JRNL--680074
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 3 Vol. 23; ISSN 1070-664X
• Publisher: American Institute of Physics (AIP)Copyright Statement
• Country of Publication: United States
• Language: English