Plasma record in China

On 27 June, the Experimental Advanced Superconducting Tokamak (EAST), in Hefei, China, sustained a plasma for a record 411 seconds. The long lifetime was achieved by replacing the inductive current with an RF-driven current and by coating the tokamak wall with lithium, explains General Atomics’s Vincent Chan, who is familiar with the experiment.

Jiangang Li, director of EAST, says the demonstration of “plasma control, sustained stability, safe handling of superconducting coils, and plasma–wall interactions under steady-state conditions” is an important step toward building ITER, the international fusion test reactor under construction in Cadarache, France.

Completed in 2006, EAST is one of a generation of new superconducting tokamaks in Asia. South Korea’s KSTAR is, like EAST, about one-quarter the size of ITER; a smaller one in India and a larger one in Japan are currently being built. Those facilities all use deuterium, not ITER’s combination of deuterium and tritium, and they work at lower plasma density, temperature, current, and magnetic field. But, says Chan, “what you do is [conduct] experiments on these machines and then translate the knowledge to optimize ITER operation.”