For far too long, fusion has been dismissed as a pipe dream. As many have pointed out, we seem to believe that we will have fusion generators within the next five-ten years; of course, analysts felt this way five-ten years ago.
There is some truth to this perception. British physicist Arthur Eddington first proposed the concept of fusion in 1920. Since then, every few years, a new update on fusion energy pops up, claiming that it is only several years away; the time passes, and the cycle begins anew.
This time though, things might actually be different. A rush of new scientific advances, along with a groundswell of funding (from both the government and private individuals), might finally render fusion a reality. There have been too many milestones, major and minor, for us to ignore the imminent possibility of fusion any longer.
Essentially, we have a way to get there. True, obstacles remain–but in terms of fundamentals, we are almost there.
In terms of mechanics, fusion is a fairly simple process (not to mention the physics behind the limitless energy, both light and heat, of the stars). Two hydrogen atoms are smashed together with overwhelming force, fusing into a new element. Because hydrogen atoms each have one proton, this new element will have two protons; yet this mass is still less than the combined mass of both hydrogen atoms. As such, the difference is released as energy.
As you can see, the problem lies in starting and sustaining the reactions. There are technical limitations, among other problems: for instance, heating the hydrogen fuel to a very high temperature (in the hundreds of millions of degrees) to containing and channeling this high heat and plasma. More importantly, just because we can start the reaction doesn’t mean we can sustain it; previously, the vast majority of fusion attempts were successful at beginning very short-lived fusion processes, with little idea of how to sustain it.
Towards that end, scientists have some ideas. While the Sun contains plasma with its gravitational pull, humans have to rely on tools like magnets or lasers. Unfortunately, these methods are imperfect; any escaping plasma can cause the system to shut down. A number of long-pulse or sustained magnetic confinement systems are being researched such as tokamaks, a doughnut-shaped device that holds plasma in place with powerful magnets, and stellarators, which, while also using magnetic fields, create very different plasma shapes.
Both designs are promising. In 2016, a stellarator-type generator, the Wendelstein 7-X of Germany, created a small sample of superheated hydrogen plasma (170 million degrees). Though the Wendelstein team was only able to harness it for a very short period of time (a quarter of a second), they successfully did so with the use of magnetic fields, thus proving a long-held assumption.
Yet the Wendelstein team isn’t the only group to see success. Later that year, the Korean Superconducting Tokamak Advanced Research (K-STAR) system was able to sustain plasma for nearly 70 seconds, breaking all records. Unlike the Wendelstein generator (a stellarator which uses magnetic fields), K-STAR used a 3D spinning field, which allowed higher plasma temperatures (but lower pressure). The breakthrough is that K-STAR can prolong stable plasma life–a key step to realizing any fusion generator.
And that’s not all. China’s EAST fusion generator sustained plasma at over 90 million degrees for 102 seconds. Meanwhile, the massive (ITER) is under construction, with a projected completion date of 2030. ITER is backed by thirty nations, and is certainly one of the most significant scientific projects in human history.
Still, much work remains to be done in order to bridge the gap between the theoretical and the
practical. Princeton hopes to solve this with its NSTX-U generator, which will serve less as a prototype than a technology demonstrator. Among the questions it seeks to address will be the optimal shapes of tokamaks, whether liquid lithium or carbon graphite will make the best wall
lining (essential to reduce corrosion), and other concrete considerations. For now, owing to cuts in funding, there are very few fusion generator experiments within the United States.
Fusion could very well come about much sooner than we think. Yes, technical challenges remain, but we continue to make progress each year. More importantly, these experiments have proven something: that humans can, in fact, create and sustain fusion reactions, at least for a short while. Now it’s just down to the engineering details.
For Maximus Yaney’s thoughts on Entrepreneurship read this piece here.
