Stellerators using magnetic fields could be the future of fusion
US and German scientists have suggested that nuclear fusion devices could use devices called stellerators to confine plasma within "twisty" 3D magnetic fields, a different approach to the symmetrical or 2D fields that tokamaks create. This twisty configuration allows the plasma to be controlled without inducing the gas, which has to happen in tokamaks. This cuts the risk of disruptions and shut downs, which frequently happens in tokamaks.
 

Physicists are starting to look toward stellarators as the new model of future fusion reactors by observing the potential of utilizing magnetic fields.

According to Phys.org, Sam Lazerson of the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL) and German scientists are experimenting with the Wendelstein 7-X (W7-X) fusion energy device called a stellarator.



The findings reveals an "error field" or a deviation from the design of less than a part in 100,000. These results can point towards the verification of just how feasible are stellarators as reactors.



W7-X is the largest and most sophisticated stellarator in the world. It was finished in 2015 by the Max Planck Institute as the vanguard for stellarator design.



Stellarators are able to confine the hot charged gas that is plasma into its twisty (or 3-D) magnetic fields. This is vastly dissimilar to the symmetrical or 2-D fields that tokamaks create.



This twisty configuration will enable stellarators to control the plasma without any need to induce the gas, unlike in tokamaks. This means stellarators run little risk of being disrupted and shut down, which commonly happens in tokamaks.



The PPPL designed and delivered five barn door-sized coils to fine-tune the magnetic fields. An electron beam is fired along the lines. Afterwards, a cross-section of the entire surface is obtained by a fluorescent rod to intersect and sweep through the lines.



This "cage" not only highlights the efficiency in design but also the cooperation of the United States to the endeavor.



The results revealed a fidelity to the design of the magnetic field. The discrepancy means the stellarator is incredibly accurate not just in the engineering of a fusion device, but in the measurement of magnetic topology as well.



The W7-X is the most recent of the stellarator concept. According to Phys.org, the concept was originally designed by Lyman Spitzer from Princeton University, and also the founder of PPPL, in the 1950s. The stellarators gave way to tokamaks a decade later, as its doughnut shape is easier to design and build.



Interestingly, the interest in stellarators has developed some decades later after advancements in plasma theory. Experiments with the W7-X can finally reveal if stellarators may be the right step for fusion energy utilization.