Speaker: Jonathan Menard
NSTX-U Recovery Director, NSTX-U Research Head, Principal Research Physicist
Princeton Plasma Physics Laboratory
Title: NSTX-U Recovery and Ideas for Next-Step Low-A Tokamaks
Abstract: The National Spherical Torus Experiment (NSTX) underwent a major upgrade to become NSTX Upgrade (NSTX-U). NSTX-U mission elements include: exploring unique Spherical Torus/Tokamak (ST) parameter regimes to advance predictive capability for ITER and beyond, developing solutions for the plasma–material interface challenges, and advancing the ST as a possible fusion nuclear science facility (FNSF) or pilot plant. During the first year of operation in 2016, NSTX-U obtained promising initial results but a poloidal field magnet failure stopped device operations. This and other technical issues resulted in the initiation of an NSTX-U Recovery Project to restore facility operation as a reliable user facility capable of accessing new physics and operational regimes. The status and plans for NSTX-U Recovery will be described. The NSTX-U research program and facility are well aligned with a recent National Academy of Science report advocating for the U.S. to remain in ITER and to start a national program of accompanying research and technology leading to the construction of a compact pilot plant that produces electricity from fusion at the lowest possible capital cost. Lower aspect ratio tokamaks may be particularly well suited for the compact pilot plant approach by combining high plasma beta with advanced high-current-density and high-field superconducting magnets to access high fusion power density at reduced cost. The performance of the tokamak fusion systems have recently been assessed using a range of core physics and toroidal field magnet performance constraints to better understand which parameters most strongly influence the achievable fusion performance. These results will also be described.
*This work is supported by US DOE Contract No. DE-AC02-09CH11466.
Title: On!NSTX-U Recovery and Ideas for Next-Step Low-A Tokamaks