Updated: Mar 4
Fusion is the energy that powers the stars.
Our Sun is a gigantic fusion device, the biggest in our solar system. In the core of the Sun, hydrogen atoms move at incredible speed. Light atoms of hydrogen fuse into one heavier atom of helium. The reaction releases lots of energy in the form of light and heat.
600 MILLION Every second our Sun coverts 600 million tonnes of hydrogen into helium.
Bringing Fusion to Earth
To replicate the fusion reaction, we need two kinds of hydrogen: deuterium and tritium. But because they are both positively charged they tend to repel one another. On the Sun, due to the strong gravity, hydrogen atoms fuse at 15 million°C. On Earth, however, because of the weaker gravitational forces, they need to be heated at temperatures as high as 150 million °C in order to collide.
Deuterieum can be found in sea water. We have enough supplies to last millions of years. Tritium can be generated from lithium, extracted from the crust of the earth.
For decades scientists have been trying to figure out how to produce this energy through various experiments. Although the principle is simple, they face several challenges. At 150 million °C, hydrogen atoms crush and end up forming an ‘electrically-charged gas’ known as plasma.They came up with the idea of a Tokamak: a chamber using a powerful magnetic field to contain the hot plasma.
On Earth, atoms must be heated at 150 million °C in order to collide so that they generate a fusion reaction. This is how they form an ‘electrically-charged gas’ known as plasma—the fourth state of matter.
Latest research shows that spherical tokamaks are much more efficient at producing energy than conventional tokamaks.
The finding opens a path to rapid development of fusion power, made possible by the latest breakthroughs in high temperature superconducting magnets.
OXFORD, England, March. 01, 2021 — Tokamak Energy. A new analysis of experimental data from Princeton Plasma Physics Laboratory and Culham Centre for Fusion Energy demonstrates that spherical tokamaks can have an efficiency ten times higher than conventional tokamaks such as JET and ITER. High efficiency is an essential requirement for making electricity from compact, relatively inexpensive fusion power plants, and tokamaks are the leading fusion power device. With their compact “cored apple” rather than doughnut shape, spherical tokamaks are particularly attractive for fusion power production. They operate at a high ratio of plasma pressure to magnetic field and at high values of self-driven “bootstrap” current that spontaneously arises within the fusion plasma.
This new paper by Alan Costley and Steven McNamara published in Plasma Physics and Controlled Fusion (https://dx.doi.org/10.1088/1361-6587/abcdfc) shows for the first time how this difference impacts performance under reactor conditions. The paper is already one of the “most read” articles in the prestigious peer-reviewed journal. This repeats the success of Alan Costley, who topped the “most read” charts with a ground-breaking 2015 paper showing that tokamaks did not have to be huge to be power-generating.
The paper indicates how multiple engineering challenges will have to be overcome to turn theory into reality to construct a compact fusion power plant. For example, high-temperature superconductors (HTS) can provide compact, high-field magnets, and significant progress is being made with their development at Tokamak Energy and elsewhere. Tokamak Energy’s proven design of HTS magnets is uniquely suitable for spherical tokamaks. The results of this latest physics study and the novel magnet technology offer the tantalising possibility of a compact, high-performance fusion module in a relatively short time scale.