Advanced Projects at PPPL‎ > ‎Stellarator R&D‎ > ‎Meetings‎ > ‎2014‎ > ‎

02 (February)

Date: February 12, 2014 (Team Meeting)

SUMMARY

Program Update  (H. Neilson)

  • Recent Highlights
    • LHD physics papers by N. Pablant and by D. Mikkelsen are in co-author review
    • W7-X XICS project had a successful CDR; PDR planned for 24 April
    • W7-X CDU Scraper Element CDR planned for early April.
    • W7-X Trim Coils: all coils and power supplies have been installed.
    • A stellarator community delegation met with DOE-Fusion Energy Sciences on 30 Jan.  
      Slides are posted at: https://sites.google.com/a/pppl.gov/advanced-projects/home/stellarator-r-d/stellarator-meetings/2014/february-12
    • Plans for 2014 conference participation and on-site collaborations at W7-X and LHD were summarized.

XICSs and LHD Transport (N. Pablant)

  • Status of W7-X XICS Project was summarized
  • Experimental proposals for W7-X OP1.1 were summarized. 
  • Goals are to
    • 1) Measure profiles of Te, Ti, ne, and Vpol and
    • 2) Determine transport properties.
  • Status of paper on transport analysis of LHD high-Te plasmas was summarized, highlighting open issues. 

Magnetics & Equilibrium (S. Lazerson)

  • Status of several publications, in preparation or in-process, was summarized
  • Status of W7-X field error correction studies was summarized. 

"Chaotic Coordinates" for the LHD magnetic field (S. Hudson with Y. Suzuki, NIFS)

  • A new method for constructing straight-field-line coordinates for stellarators was described.
  • A key result is that a collection of "almost-invariant" surfaces can be constructed quickly, and the radially outward magnetic field-line flux across these surfaces determines how important each surface is in confining the plasma. Here, "almost invariant" means a rational "quadratic-flux minimizing surface", which is closely related to a rational "ghost-surface"
  • The method provides a systematic way of locating the last closed surface; in reality there is generally a hierarchy of "partial boundaries."

Gyrokinetic Validation in Stellarators (D. Mikkelsen

  • Progress on paper analyzing LHD "impurity hole" regime was made during recent visit by K. Tanaka (NIFS). Paper is in review by the LHD steering committee.
  • Work on a gyro kinetic benchmarking paper (with NIFS colleagues) has resumed. Target submission to NIFS for co-author review in early March. 

Update on Columbia Stellarators and their Microwave Heating (F. Volpe, Columbia Univ.)

  • Construction of CIRCUS (tokamak-stellarator hybrid based on tilted planar coils) was completed. Testing in progress.
  • A plasma heating upgrade (10 kW, 2.45 GHz) for the CNT experiment is in progress  – magnetron delivery is expected in April. Expected parameters were presented. 

Summary by: Hutch Neilson, 17 February 2014