Song Yuntao, Vice President of CAS’s Hefei Institutes of Physical Science (HFIPS), and Gong Xianzu, chief operator of EAST experiment, were celebrating in the EAST hall after the breakthrough of “artificial sun”. [IMAGE: XINHUA NEWS]

At 21:00 on April 12, the first 403-second steady-state H-mode plasma was achieved on EAST, setting a new record of pulse length on high performance operation in tokamaks. On the next day at 19:00, the EAST team repeated this operational scenario, demonstrating the reliability of the device.

The head of Division of EAST Physics and Experimental Operations, Dr. Gong Xianzu explains that there are several distinctive features in this development:

1) A full non-inductive plasma with high density (ne/nGW~0.7) and high bootstrap current (fBS>50%) by RF heating with zero torque injection; 2) H-factor (H98,y2) around 1.35 with internal transport barrier by electron dominant heating; 3) Key issues on particle and heat balance with actively cooling tungsten divertor (recycling coefficient R~0.92 and TSurf@Div<600℃); 4) Small ELMs throughout the discharge, with high core performance (βP~2.5 / βN~1.5).

Breakthrough was achieved in EAST with new plasma development. [IMAGE: EAST TEAM]

This major breakthrough made in EAST physics experiment, Gong believes, further verifies the feasibility of steady-state H-mode operation for future fusion reactors.

EAST’s success is a joint effort, a statement of extensive cooperation in scientific fields, said ASIPP Director-General Song Yuntao. EAST team has worked together closely with their collaborators at home and abroad over the past decades solving a series of frontier physics and technical issues, such as plasma configuration control, high efficiency of RF heating and current drive, plasma-wall interactions, and real-time diagnostics for key plasma parameters.

In recent years, with support from government authorities, the Chinese Academy of Sciences and domestic and international collaborators, EAST device in ASIPP has been continuously upgraded to enhance fusion performance in support of ITER operation and the construction of a Chinese fusion reactor.

The first experimental campaign on EAST in 2023 will continue for about two or three months and the second one has been scheduled for the winter of this year.

At 21:00 on April 12, the first 403-second steady-state H-mode plasma was achieved on EAST. [IMAGE: EAST TEAM]


Source: Institute of Plasma Physics,

Hefei Institutes of Physical Science (HFIPS),

Chinese Academy of Sciences

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