The EAST superconducting tokamak made an advance in 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 3 July 2017.

The obtained high confinement mode features the edge localized modes (ELMs) with small perturbation amplitude under the condition of low-momentum injection with pure RF (LHCD, ICRF, ECRH) wave heating, 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 being maintained at > 50% Greenwald density limit, EAST achieved a fully non-inductive current driven steady-state high-performance plasma with a confinement enhancement factor H_98y2 greater than 1.1 for more than 100 seconds.

Basic parameters of the world’s longest 101.2 s high confinement discharge achieved on EAST (Bt=2.5T, P_RF=3.0MW, n_e/n_eGW=0.55, Te=4.0KeV, H_98y2=1.1, Upper single null configuration ). Image by the EAST Team

All the plasma parameters, including recycling, particle and heat fluxes, reached truly steady-state after 20s, the wall saturate time for the W divertor and maintained stable to the end of discharge.

Chief Operator GONG Xianzu shared the good news and his excitement with some EAST partners home and abroad in 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 on both 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 of joint efforts,” said GONG. The EAST team has worked together with their collaborators at home and abroad over the past decade to solve a series of key technical and physical issues closely related to the steady-state operation, and carried out in-depth scientific research on integrated operation scenarios with effective coupling of multi-scale physical processes.

EAST 2017 experimental campaign will go on for about one more month and the second round of experiment will start in autumn of this year.