WEST claims latest plasma confinement record
The French magnetic confinement fusion tokamak known as WEST maintained a plasma in February for more than 22 minutes—1,337 seconds, to be precise—and “smashed” the previous record plasma duration for a tokamak with a 25 percent improvement, according to the CEA, which operates the machine. The previous 1,006-second record was set by China’s EAST just a few weeks prior. Records are made to be broken, but this rapid progress illustrates a collective, global increase in plasma confinement expertise, aided by tungsten in key components.
The WEST plasma reached a temperature of 50 million degrees. (Photo: CEA)
“WEST has achieved a new key technological milestone by maintaining hydrogen plasma for more than twenty minutes through the injection of 2 MW of heating power. Experiments will continue with increased power. This excellent result allows both WEST and the French community to lead the way for the future use of ITER,” said Anne-Isabelle Etienvre, director of fundamental research at the CEA.
Expect this record to fall: Just one year ago, in February 2024, the CEA was celebrating an experimental campaign that saw WEST optimize its high-power ion cyclotron resonance heating (ICRH) antennas and achieve a plasma duration of 258 seconds. EAST’s latest record was set on January 20. Now, WEST is targeting ever longer plasma durations.
“Over the coming months, the WEST team will double down on its efforts to achieve very long plasma durations—up to several hours combined—but also to heat the plasma to even higher temperatures with a view to approaching the conditions expected in fusion plasmas,” the CEA said in February.
Past life: WEST didn’t achieve its first plasma until 2017, and it was “inaugurated” within the Cadarache Institute for Research on Magnetic Confinement Fusion (CEA-IRFM) in April 2018. But the device first operated in 1988 under another name.
WEST’s predecessor, Tore Supra, took its name from the toroidal superconducting magnets featured in its design. After operating until 2010—and achieving a plasma confinement of 6 minutes and 30 seconds—the device was shut down for extensive modifications to make its research program more relevant to ITER. Poloidal coils were installed inside the vacuum enclosure to introduce a divertor configuration with a zone of zero poloidal magnetic field, and plasma-facing components were replaced to achieve a fully metallic environment in the vacuum enclosure, including tungsten divertor components. The modifications also included upgraded heating devices and diagnostics.
In a nod to EAST, which started operating in 2007, the former Tore Supra was renamed WEST (for Tungsten [the atomic symbol of which is W] Environment Steady-state Tokamak).
WEST in context: WEST is located at the CEA Cadarache site in southern France, just a few miles from the ITER construction site. In June 2024, ITER’s schedule was pushed back, and deuterium-deuterium operations are now anticipated in 2035.
As the ITER team grapples with repairing and refitting key components, WEST’s experimental program continues. According to CEA-IRFM, “The ambition is to increase the heating power from 2 MW to 10 MW, still over durations of the order of 1,000 seconds, a power that corresponds to a fusion power of the order of GW in a machine the size of ITER. This will allow the evaluation of the lifetime of the tungsten components facing the plasma in these extreme conditions.”
Other magnetically confined tokamak fusion machines have provided data relevant to ITER, including JET, the Joint European Torus tokamak in the United Kingdom, which also got a tungsten plasma-facing makeover. While JET was permanently shut down in late 2023, it first achieved the current record for the highest fusion energy, producing a consistent 69 megajoules for 5 seconds.
Other tokamaks in operation include the Department of Energy’s DIII-D facility in San Diego, Calif.; JT-60SA in Japan (currently the world’s newest and largest tokamak); EAST in China; and KSTAR in South Korea.
