What’s New

A major challenge in the development of fusion energy is maintaining the ultra-hot plasma of a fusion device in a steady state, or stable form. While superconductors can allow a fusion reactor to operate indefinitely, controlling the plasma with superconductors presents a challenge because engineering constraints limit their response time compared to the more energy consuming copper coils.

The slower pace makes it difficult to operate a stable discharge with the large plasma volume or extended vertical height required for producing fusion power. Exploration of this issue in a current superconducting device is particularly helpful for ITER, which will be operational in 2025.

At the leading edge of this control challenge is the Korea Superconducting Tokamak Advanced Research (KSTAR) device, one of the largest superconducting tokamaks in the world. Its superconductors are made of niobium and tin, the same conductor that is planned for use in ITER.

A team of US and Korean researchers, led by physicist Dennis Mueller (photo) of the Princeton Plasma Physics Laboratory (PPPL), has now sharply improved the stability of the elongated plasma in KSTAR, setting an example for how to address similar issues in other superconducting devices such as ITER. The successful control method, demonstrated this summer by Mueller and physicists from the National Fusion Research Institute (NFRI) in South Korea, which operates the tokamak, and General Atomics in San Diego, caps years of effort to control the vertical instability, which had allowed the plasma to bounce up and down in the 11-foot-high vacuum vessel.

See how they did it in the full article on the PPPL website.

It is inscribed in bold letters on the large poster that is affixed to the ITER Assembly Hall: harnessing fusion energy is akin to "bringing the power of the Sun to Earth."

And it is true: like the Sun, the ITER Tokamak will produce energy by fusing hydrogen nuclei into helium.

The fusion reaction in our machine, however, is not like that which occurs in Sun-like stars. Although the end product (helium) and the ingredients (hydrogen isotopes in one case, hydrogen in the other) are the same, the nature of the process is profoundly different.

In a recent article on the Forbes website astrophysicist Ethan Siegel explains how "hydrogen-fusing-into-helium makes up less than half of all nuclear reactions in our Sun," and how the nuclear physics in stellar bodies abounds in "strange, unearthly phenomena."

The inscription on the Assembly Hall remains nonetheless true. ITER is indeed "bringing the power of the Sun to Earth." It's just that stars and tokamaks have different ways of obtaining a similar result.

Click here to read the full Forbes.com article.

Fourteen authors and one illustrator share their passion for fusion in special October issue of Fusion in Europe. The issue contains a variety of topics ranging from ITER, JET, Brexit, material science, the Lawson Criterion, plasma turbulence and the history of fusion research in Mexico.

What is also special about the issue is that most of the authors are students or young researchers from around the world. The newsletter is thus a window onto the views of the next generation of fusion professionals and enthusiasts.

Click here to view the full October issue of Fusion in Europe.