Wendelstein 7-X Fusion Breakthrough: Stellarators Lead

Wendelstein 7-X Breaks Fusion Records: Stellerators Outshine Tokamaks

The Wendelstein 7-X experimental fusion reactor in Germany has achieved a groundbreaking milestone, reaffirming the potential of stellarators over the more commonly pursued tokamaks. Scientists from the Max Planck Institute for Plasma Physics in Greifswald have set new records in fusion research, creating a promising benchmark for controlled nuclear fusion.

Stellarators vs. Tokamaks

Stellarators are advantageous due to their inherent stability, as they do not require a current to run through the plasma for confinement. Instead, a complex external magnetic field system holds the plasma in place, which reduces instability concerns prevalent in tokamaks. However, due to their intricate design, stellarators have had higher production and tuning costs. Despite the global focus on tokamaks, like the massive ITER project, stellarators offer the potential for smaller, more commercially viable reactors.

Record-Breaking Experiment

In a recent experimental cycle, the Wendelstein 7-X achieved unprecedented combinations of fusion parameters: temperature, plasma density, and confinement time. The experiment highlights a new fuel injection system with continuous feeding of fuel combined with pulsed heating, maintaining the required plasma temperature of up to 30 million °C. Over 43 seconds, 90 frozen hydrogen pellets were injected at speeds up to 800 m/s, synchronized with microwave pulses to enhance plasma stability.

Significant Fusion Gains

The experiment also saw a rise in energy turnover to 1.8 GJ during a six-minute cycle, surpassing the previous record of 1.3 GJ set in February 2023. Energy turnover is crucial as it combines heating power and plasma duration, indicating the reactor’s performance in maintaining high-energy plasma. This breakthrough showcases a viable path for future power-generating fusion plants.

IPP scientists emphasized that these achievements are more than mere numbers; they are a significant advance in validating stellarator concepts, made possible by outstanding international collaboration.