04 (April)

Date: April 11, 2013


Program Updates, H. Neilson

  • Progress on W7-X trim coils:
    • Last trim coil and all instrumentation interface modules ("IO Boxes") were delivered to IPP.
    • Power supplies: On track to deliver by end of the fiscal year
  • W7-X transition to research:
    • Formal DOE-IPP research partnership agreement is in negotiation. PPPL has been appointed the U.S. lead institution for the W7-X collaboration.
    • We still anticipate a call for proposals for international stellarator collaborations in FY-13, but we don't know when.
  • Domestic program planning:
    • FESAC completed its facility review and ranked quasi-symmetric stellarator research high in scientific importance.
    • We still anticipate a call for proposals for exploratory research in FY-13, but we don't know when.
  • Stellarator work plan status and priorities for the rest of the year were reviewed.


Research on LHD Using XICS - N. Pablant

  • Progress made during a recent trip to NIFS in transport analysis of LHD high electron-temperature, electron-cyclotron heated plasmas was summarized. The work uses the NIFS analysis code TASK3D
  • The aim of the study is to determine thermal diffusivity coefficients for comparison with theory and other experimental techniques, and to compare transport properties before and after the start of the high temperature phase.
  • Progress reported includes: integration of XICS profiles into TASK3D, partial integration of U.S. equilibrium reconstruction code into TASK3D, identification of an LHD shot for initial analysis, and completion of a test run demonstrating successful integration of the new elements.
  • The report also highlighted open issues including unavailability of ECH power deposition data and problems with the electron-ion power transfer calculation.

Turbulence Optimization of QA Plasmas (LDRD study)- H. Mynick

  • Starting with a number of previously-reported turbulence-optimized plasmas, a second optimization has been applied to improve kink and ballooning stability, while maintaining good neoclassical and turbulent transport.
  • Status was summarized.

Coil Optimization (LDRD study) - J. Breslau

  • COILOPT++ has been modified to allow multiple winding surfaces. This allows the modular coils and saddle coils to lie on different surfaces.
  • A manual coil editing capability has been added to give the user an additional means to correct problematic features on the coils.
  • Action: clarify definition of normalized RMS field error being used as a metric, and establish standard for adequacy. (Breslau)
  • Plans for continuing work were summarized.

Equilibrium reconstruction- S. Lazerson

  • Continued progress in improving the STELLOPT optimization methodology was reported.
  • Modeling of W7-X magnetic diagnostics and sensitivity to beta was reported.
  • Action: investigate why diamagnetic loops don't all measure the same flux.
  • Work on 3D equilibrium modeling for tokamaks, i.e. ITER and NSTX, was highlighted.
  • Plans for continuing work were summarized.

Gyrokinetic Validation in Stellarators - D. Mikkelsen

  • Recent progress in benchmarking of gyrokinetic codes using an LHD case was highlighted.
  • GS2 code is being used to investigate the LHD high-Ti "impurity hole" regime. The code currently predicts inward carbon impurity flux, opposite to what is seen experimentally. Investigation continues.

W7-X Tasks / Plans at ORNL - J. Harris, ORNL

  • Physics and engineering design of the W7-X scraper element has progressed. A Final Design Review (FDR) will be held later this fiscal year.
  • A prototype scraper element will be built and tested in a ORNL-IPP collaboration with PLANSEE as an industrial partner. Funding to PLANSEE via a German government grant, separate from fusion, was enabled partly on the strength of the U.S. collaboration.
  • It is planned that an uncooled version of the scraper element (perhaps 2 units) will be implemented during the test divertor unit (TDU) phase of W7-X operations.
  • A strategy for implementing pellet injection in a ORNL-IPP-NIFS collaboration is being developed.

Summary by: Hutch Neilson, 17 April 2013