High energy particles in W7-X

First high-energy particles generated with radio waves at the Wendelstein 7-X stellarator

Wendelstein 7-X (W7-X) is the world’s largest stellarator, built at the Max-Planck Institute for Plasma Physics in Greifswald, Germany, to advance fusion energy research by confining a hot plasma in a steady-state magnetic field. One of the major challenges in such devices is the confinement of fast (high-energy) particles, essential for efficient plasma heating and fusion performance in future fusion power plants of this type.

For the first time, high-energy helium-3 particles have been successfully generated in W7-X using powerful radio-frequency waves over the last weeks. This achievement, made possible by the Ion Cyclotron Resonance Heating (ICRH) antenna (see Figure), provides a major tool towards proving the stellarator’s potential as a viable fusion reactor

The ICRH system at W7-X was jointly developed through a close collaboration between Plasma Physics Laboratory of the Royal Military Academy in Brussels and the Institute IFN-1, the result of years of dedicated development and engineering. Future experimental campaigns will deepen our understanding of energetic particle physics in stellarator configurations and paving the way for further fusion advancements.

This is a nice illustration that fusion science goes beyond creating tomorrow’s energy source—it also reveals astonishings secrets about our very own star, the Sun! The same physical process that created the energetic particles in Wendelstein 7‑X help explain why sometimes clouds are detected around our Sun that contain up to 10,000 times more helium-3 than what we normally see in the solar atmosphere or solar wind. Scientists spotted such striking helium-3 clouds again on 24 October last year, detected by the Solar Orbiter spacecraft.