Experimental Advanced Superconducting Tokamak

Experimental Advanced Superconducting Tokamak. It is a major nuclear fusion research device located at the Institute of Plasma Physics in Hefei, China. As one of the world's first fully superconducting tokamaks, its primary mission is to explore the physics and engineering solutions required for steady-state operation of future fusion reactors. The facility is a cornerstone of China's fusion program and plays a significant role in the global quest for fusion power.

Overview and Mission

The construction of the device was approved as a key national project by the Chinese Academy of Sciences in the late 1990s. Its core mission is to advance the scientific understanding of plasma physics under conditions relevant to a practical fusion energy source. A central goal is to achieve and sustain high-performance plasma discharges for extended durations, directly informing the design of next-step devices like ITER and CFETR. The project represents a major technological leap for the Asian physics community, establishing Hefei as a prominent hub for thermonuclear fusion research.

Design and Technical Specifications

The machine features an advanced design with all magnetic coils constructed from niobium-titanium and niobium-tin superconducting materials, allowing for long-pulse operation. Its major radius is 1.85 meters, with a minor radius of 0.45 meters, and it can generate a toroidal magnetic field of up to 3.5 Tesla. Key innovations include a fully actively cooled divertor capable of handling high heat fluxes and extensive internal components designed for advanced plasma control. The heating and current drive systems are comprehensive, employing lower hybrid current drive, ion cyclotron resonance heating, and neutral beam injection technologies developed in collaboration with institutions like the Princeton Plasma Physics Laboratory.

Key Experiments and Achievements

The device has set multiple world records for high-confinement plasma duration. In 2017, it achieved a fully non-inductive, steady-state H-mode plasma for over 100 seconds, a landmark result for superconducting machines. A major breakthrough came in 2021 when it sustained a plasma at 120 million degrees Celsius for 101 seconds, and later achieved a peak temperature of 160 million degrees Celsius. These experiments have provided critical data on plasma stability, edge-localized modes mitigation, and heat exhaust management, directly benefiting the operational planning for ITER. The team's work on long-pulse scenarios was recognized with awards from the International Atomic Energy Agency.

Role in International Fusion Research

The facility operates as an open international platform, hosting scientists from around the world under agreements with organizations like EURATOM and the United States Department of Energy. It is a vital contributor to the ITER project, testing prototype components such as divertor cassettes and validating physics models for disruption prediction. Collaborative experiments with other major facilities, including JT-60SA in Japan and DIII-D in the United States, are routine. Its data is integral to global research networks like the International Tokamak Physics Activity, helping to refine the roadmap for DEMO, the demonstration fusion power plant.

Future Development and Goals

The immediate roadmap involves further extending plasma performance parameters and testing advanced tungsten-based plasma-facing materials. A major upcoming upgrade focuses on enhancing its heating and current drive capabilities to support even longer and hotter discharges. The knowledge gained is being directly fed into the engineering design phase of the CFETR, which aims to bridge the gap between ITER and commercial fusion. The ultimate objective is to provide the essential physics basis and technological validation required to make fusion energy a viable and sustainable reality within the coming decades.

Category:Experimental tokamaks Category:Nuclear fusion research facilities Category:Chinese Academy of Sciences Category:Buildings and structures in Hefei Category:Research institutes in China