China's pioneering fully superconducting tokamak at ASIPP in Hefei — the first tokamak to achieve both superconducting toroidal and poloidal field coils, holding world records for sustained plasma duration exceeding 400 seconds.
The Experimental Advanced Superconducting Tokamak (EAST), also known by its Chinese designation HT-7U, is a fully superconducting tokamak operated by the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) in Hefei, Anhui Province. EAST achieved first plasma in September 2006 and became the world's first tokamak to employ superconducting coils for both its toroidal and poloidal magnetic field systems.[1]
EAST was designed as a testbed for long-pulse, high-performance plasma operations directly relevant to future fusion power plants and ITER. Its major radius is approximately 1.85 meters with a minor radius of 0.45 meters, and it operates with a D-shaped plasma cross-section capable of single-null and double-null divertor configurations.
The tokamak features an ITER-like tungsten divertor installed during upgrades in 2014, replacing the earlier carbon-based plasma-facing components. This upgrade was critical for studying plasma-wall interactions under conditions more representative of future reactors.[2]
EAST has progressively extended the frontiers of sustained plasma operation. In 2017, the device achieved a 101.2-second H-mode plasma discharge, setting an early record for sustained high-confinement operation. In December 2021, EAST sustained a plasma at 70 million degrees Celsius for 1,056 seconds, demonstrating remarkable long-pulse capability.[1]
In April 2023, EAST achieved a steady-state high-confinement plasma lasting 403 seconds, setting a new world record for the longest sustained H-mode operation in a tokamak. This milestone demonstrated the viability of long-pulse operation with active control of plasma instabilities, heat exhaust, and particle recycling — all essential capabilities for a fusion power plant.[3]
EAST serves as a critical testbed for ITER-relevant physics and technology. Its experiments have contributed directly to understanding long-pulse plasma control, real-time instability suppression, and divertor heat flux management. China's participation in ITER is closely linked to the operational experience gained on EAST.
Looking beyond ITER, EAST research feeds into the design of the China Fusion Engineering Test Reactor (CFETR), a proposed next-step device that would bridge the gap between ITER and a demonstration fusion power plant. CFETR aims to demonstrate tritium self-sufficiency and steady-state operation at reactor-relevant parameters.[2]
Current research on EAST focuses on extending high-performance plasma duration further, developing advanced divertor concepts for managing extreme heat loads, and refining real-time control systems for plasma instabilities including edge-localized modes (ELMs). The device also serves as a training platform for the next generation of Chinese fusion scientists and engineers who will operate ITER and CFETR.