Foreign Travel Trip Report for LLNL travel with DOE FES funding,May 19th-30th, 2012

Technical Report · Thu Jul 05 00:00:00 EDT 2012

DOI:https://doi.org/10.2172/1048480· OSTI ID:1048480

Joseph, I

I attended the 20th biannual International Conference on Plasma Surface Interaction (PSI) in Fusion Devices in Aachen, Germany, hosted this year by the Forschungszentrum Julich (FZJ) research center. The PSI conference is one of the main international forums for the presentation and discussion of results on plasma surface interactions and edge plasma physics relevant to magnetic confinement fusion devices. I disseminated the recent results of FESP/LLNL tokamak research by presenting three posters on: (i) understanding reconnection and controlling edge localized modes (ELMs) using the BOUT++ code, (ii) simulation of resistive ballooning mode turbulence, and (iii) innovative design of Snowflake divertors. I learned of many new and recent results from international tokamak facilities and had the opportunity for discussion of these topics with other scientists at the poster sessions, conference lunches/receptions, etc. Some of the major highlights of the PSI conference topics were: (1) Review of the progress in using metallic tungsten and beryllium (ITER-like) walls at international tokamak facilities: JET (Culham, UK), TEXTOR (FZJ, Germany) and Alcator CMOD (MIT, USA). Results included: effect of small and large-area melting on plasma impurity content and recovery, expected reduction in retention of hydrogenic species, increased heat load during disruptions and need for mitigation with massive gas injection. (2) A review of ELM control in general (T. Evans, GA) and recent results of ELM control using n=2 external magnetic perturbations on ASDEX-Upgrade (MPI-Garching, Germany). (3) General agreement among the international tokamak database that, along the outer midplane of a low collisionality tokamak, the SOL power width in current experiments varies inversely with respect to plasma current (Ip), roughly as 1/Ip, with little dependence on other plasma parameters. This would imply roughly a factor of 1/4 of the width that was assumed for the design of the ITER tokamak. The first studies of the implications for ITER (A. Kukushkin, ITER) have shown a great reduction in operational parameter space that, at present, can only be lifted by increasing target plate heat flux limits. During my visit to the CRPP at the EPFL, I delivered an invited talk in order to disseminate new results of the recent publication [1] on using non-axisymmetric perturbations of the SOL to control the edge plasma. I was given a tour of both the TCV tokamak and the TORPEX simple magnetized plasma device/divertor simulator. TORPEX is an excellent laboratory for exploring the physics of simple magnetized plasmas that are relevant to the scrape-off layer of a tokamak. Properly designed experiments on TORPEX can potentially be used to test the theory of controlling the edge plasma using non-axisymmetric potentials and currents in the SOL developed by LLNL described in [1].

• Research Organization: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 1048480
• Report Number(s): LLNL-TR-563591; TRN: US1204269
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BERYLLIUM
DESIGN
DIVERTORS
EDGE LOCALIZED MODES
ELECTRIC CURRENTS
GAS INJECTION
HEAT FLUX
ITER TOKAMAK
MAGNETIC CONFINEMENT
MELTING
MITIGATION
PHYSICS
PLASMA
RETENTION
SOLS
TARGETS
TCV TOKAMAK
TUNGSTEN
TURBULENCE