China's Experimental Advanced Superconducting
Tokamak (EAST) made an important advance by achieving a stable 101.2-second
steady-state high confinement plasma, setting a world record in long-pulse
H-mode operation on the night of July 3rd.
The obtained high confinement mode features
edge-localized modes (ELMs) with small perturbation amplitude under the
condition of low-momentum injection with pure RF (LHCD, ICRF, ECRH) wave
heating, and an actively cooled ITER-like monoblock tungsten divertor.
With effective control of the divertor target heat
load and tungsten impurity influx, and the center chord average electron
density maintained at > 50% of the Greenwald density limit, EAST achieved a
fully non-inductive, current-driven, steady-state plasma with a confinement enhancement
factor H98y2 greater than 1.1 for more than 100 seconds.
All the plasma parameters, including recycling, and
particle and heat fluxes, reached a truly steady state after 20 seconds—the
wall saturation time for the W divertor—and remained stable until the end of
the discharge.
Chief Operator GONG Xianzu shared the good news and
his excitement with some EAST partners at home and abroad at midnight via
social media. GONG has witnessed every advance made on the machine as well as
its setbacks, since his first operation of EAST in 2006. This breakthrough, he
said, indicates EAST will "continue to play a key role in both the physics
and engineering fronts of steady-state operation, and has significant
scientific implications for the International Thermonuclear Fusion Reactor
(ITER) and the future China Fusion Engineering Test Reactor (CFETR)."
"It is a success based on joint efforts,"
said GONG. The EAST team has worked together with collaborators at home and
abroad over the past decade to solve a series of key technical and physical
issues closely related to steady-state operation, and carried out in-depth scientific
research on integrated operation scenarios with effective coupling of
multi-scale physical processes. The EAST 2017 experimental campaign will go on
for about one more month; the second round of experiments will start in autumn
of this year.
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