100 million degrees Celsius for 30 seconds using a device called KSTAR
Scientists in South Korea have achieved a new milestone for nuclear fusion, the process of fusing atomic nuclei to release massive amounts of energy. They have managed to sustain a fusion reaction at a temperature of 100 million degree Celsius for 30 seconds, using a device called KSTAR (Korea Superconducting Tokamak Advanced Research).
This is an important step towards developing a viable fusion power plant, which could provide clean, safe, and virtually unlimited energy by mimicking the natural reactions that power the Sun and other starsHow does nuclear fusion work?
Nuclear fusion is the opposite of nuclear fission, which is the process of splitting atomic nuclei to release energy. Fission is currently used in nuclear power plants, but it produces radioactive waste and poses safety risks.
Fusion, on the other hand, involves combining light nuclei, such as hydrogen, into heavier ones, such as helium. This releases a huge amount of energy, as some of the mass is converted into energy according to Einstein's famous equation E=mc^2^.
However, fusion requires extremely high temperatures and pressures to overcome the natural repulsion between positively charged nuclei. The Sun achieves this by its enormous gravity, but on Earth, scientists have to use sophisticated devices to create and confine a hot, ionized state of matter called plasma
What is KSTAR and how does it work?
KSTAR is a doughnut-shaped device that uses powerful magnets to create and control plasma. It is one of several tokamaks around the world that are experimenting with fusion technology.
The main challenge for tokamaks is to achieve a stable and long-lasting plasma that can reach the temperatures and densities needed for fusion. This requires a delicate balance between heating, cooling, and confining the plasma.
The KSTAR team used a modified technique called internal transport barrier (ITB) mode, which creates a higher pressure near the center of the plasma and a lower pressure near the edge. This helps to boost the temperature and reduce the heat loss.
By applying this technique, they were able to achieve a plasma temperature of 100 million degrees Celsius for 30 seconds, which is nearly seven times hotter than the core of the Sun. This is not a record in itself, as other devices have reached higher temperatures or longer durations, but it is a significant achievement in terms of combining both heat and stability.
Why is this important and what are the next steps?
Nuclear fusion has been hailed as the holy grail of clean energy, as it could provide abundant, carbon-free, and safe energy for humanity. However, it is also notoriously difficult and expensive to achieve.
The KSTAR experiment demonstrates that fusion is not a dream, but a realistic possibility. It also shows that South Korea is a leader in fusion research, along with other countries such as China, France, and the US.
The next goal for KSTAR is to extend the plasma duration to 50 seconds by 2022, and eventually to 300 seconds by 2026. This would be the minimum time frame to demonstrate steady-state operations, which are necessary for a commercial fusion reactor.
The ultimate test for fusion will be ITER (International Thermonuclear Experimental Reactor), which is being built in France as a collaboration among 35 countries. ITER aims to produce 500 megawatts of fusion power for 20 minutes by 2035, which would be ten times more than the input power.
If successful, ITER would pave the way for DEMO (Demonstration Power Station), which would be the first prototype of a fusion power plant that could generate electricity for the grid by 2050.
