Overview of Innovative PMI Research on NSTX-U and Associated PMI Facilities at PPPL
Authors: M. Ono, M. Jaworski, R. Kaita, C. N. Skinner, J.P. Allain, R. Maingi, F. Scotti, V.A. Soukhanovskii, and the NSTX-U Team
Abstract:
Developing a reactor compatible divertor and
managing the associated plasma material interaction
(PMI) has been identified as a high priority research area
for magnetic confinement fusion. Accordingly on NSTXU,
the PMI research has received a strong emphasis.
With ~ 15 MW of auxiliary heating power, NSTX-U will
be able to test the PMI physics with the peak divertor
plasma facing component (PFC) heat loads of up to 40-60
MW/m2 . To support the PMI research, a comprehensive
set of PMI diagnostic tools are being implemented. The
snow-flake configuration can produce exceptionally high
divertor flux expansion of up to ~ 50. Combined with the
radiative divertor concept, the snow-flake configuration
has reduced the divertor heat flux by an order of
magnitude in NSTX. Another area of active PMI
investigation is the effect of divertor lithium coating (both
in solid and liquid phases). The overall NSTX lithium
PFC coating results suggest exciting opportunities for
future magnetic confinement research including
significant electron energy confinement improvements, Hmode
power threshold reduction, the control of Edge
Localized Modes (ELMs), and high heat flux handling.
To support the NSTX-U/PPPL PMI research, there are
also a number of associated PMI facilities implemented at
PPPL/Princeton University including the Liquid Lithium
R&D facility, Lithium Tokamak Experiment, and
Laboratories for Materials Characterization and Surface
Chemistry.
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Submitted to: Journal of Nuclear Materials, (September 2012)
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