Researchers from China’s Hefei Institutes of Physical Sciences announced that China’s ‘artificial sun’ just became the hottest known nuclear fusion experiment on Earth. The plasma temperature reached 100 million degrees Celsius. Our solar system’s Sun is about 15 million degrees Celsius.
The technology to harness energy from nuclear fusion is in its infancy. So, this achievement is quite significant. It is thought that 100 million degrees Celsius is the minimum temperature required for self-sustaining nuclear fusion on Earth.
The artificial Sun, is a popular name given to one of the most promising nuclear fusion experiments to date. It is because the stars derive their energy from the same process and Sun is a star. So, the project is designed to replicate the process our Sun uses to generate energy. Researchers set up the Experimental Advanced Superconducting Tokamak (EAST) fusion reactor in 2006.
A ‘Tokamak’ is a reactor design that resembles a donut — a donut that generates powerful magnetic forces to contain unimaginably hot plasma inside the reactor during nuclear fusion. The walls of a tokamak are built to absorb the massive amounts of heat from the continuous splitting of atoms in the reactor’s core.
Nuclear fusion is also called the ‘great white whale’ of global energy. A small amount of fuel can light up several powerhouses for months. Besides, unlike nuclear fission, it has no risk of radioactivity. So, the nuclear reactors like EAST are a means to exactly that: an almost infinite supply of energy that is clean.
One of the few hurdles to unleashing nuclear fusion as an energy source is sustaining the fusion reaction for longer than a handful of minutes. The longest recorded reaction is was at the Tore Supra tokamak in France (also known as WEST), for 6 minutes and 30 seconds in 2003.
In a fusion process, two lighter atomic nuclei combine to form a heavier nucleus, and at the same time, they release energy. This is the same process that powers stars like our Sun. Devices designed to harness this energy are known as fusion reactors.
Fusion processes require fuel and a highly confined environment with a high temperature and pressure, creating a plasma in which fusion can occur. In stars, the most common fuel is hydrogen, and gravity creates the high temperature and confinement needed for fusion. Fusion reactors generally use hydrogen isotopes such as deuterium and tritium, which react more easily, and create a confined plasma of millions of degrees using inertial methods (laser) or magnetic methods (tokamak and similar).