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The popular name for experimental reactors that fuse light nuclei at extreme temperatures, recreating the process that powers the Sun.
Artificial Sun is the popular name given to experimental machines that attempt to reproduce on earth the nuclear fusion reactions that power the Sun. In these devices, a gas of light isotopes of hydrogen is heated to temperatures many times hotter than the solar core until it becomes a plasma, and powerful magnetic fields hold that plasma away from the reactor walls while the nuclei fuse and release energy. Most such machines use a design called a tokamak, a doughnut-shaped chamber ringed by superconducting magnets. China's Experimental Advanced Superconducting Tokamak (EAST) and its HL series reactors are commonly described as artificial suns, as is the international ITER project under construction in southern France.
Type: ConceptRecreates nuclear fusion, the process that powers the Sun, rather than the fission used in existing nuclear power plants
Fuel is normally deuterium and tritium, two heavy isotopes of hydrogen
Requires temperatures far above those at the centre of the Sun, because the reactor cannot reproduce the Sun's crushing gravitational pressure
Matter at these temperatures exists as plasma, the fourth state of matter, in which electrons are stripped from nuclei
A tokamak confines the plasma magnetically in a doughnut-shaped chamber, so it never touches the walls
Produces no carbon dioxide and no long-lived high-level radioactive waste of the kind fission reactors generate
Frequency: Nuclear energy, including the fission-fusion distinction and ITER, appears regularly in UPSC Prelims science and technology
| Aspect | Nuclear Fusion | Nuclear Fission |
|---|---|---|
| Basic process | Light nuclei join to form a heavier nucleus | A heavy nucleus splits into lighter nuclei |
| Typical fuel | Deuterium and tritium, isotopes of hydrogen | Uranium-235 or plutonium-239 |
| Conditions required | Extremely high temperature and confinement | Occurs at ordinary reactor temperatures once initiated |
| Chain reaction risk | Stops immediately if confinement fails, so no runaway reaction | Requires active control to prevent a runaway chain reaction |
| Radioactive waste | No long-lived high-level waste | Long-lived high-level waste requiring extended storage |
| Current status | Experimental; no commercial power generation yet | In commercial use worldwide, including in India |
Atomic nuclei are positively charged and therefore repel one another. To fuse, they must be pushed close enough for the strong nuclear force to take over, and that means overcoming this electrostatic repulsion. The Sun manages it at about 15 million degrees Celsius because its enormous gravity compresses the core to extraordinary densities. A reactor on earth has no such gravity, so it compensates with temperature, heating the fuel to well over a hundred million degrees. At those temperatures no material container can hold the fuel, which is why the plasma must be suspended in a magnetic field instead — the central engineering problem of fusion.
Two magnets pushed together north-to-north resist fiercely, but if you can force them past a certain point they snap together. Fusion is that snap, and the temperature is the force needed to get past the resistance.
1,066 seconds of high-confinement plasma, up from a previous 403 seconds
China
Southern France
Seven — European Union, China, India, Japan, South Korea, Russia, United States
Institute for Plasma Research, Gandhinagar
ADITYA and SST-1 (Steady State Superconducting Tokamak)
About 15 million degrees Celsius
Fusion is the only known energy source that would combine effectively unlimited fuel with no carbon emissions and no long-lived radioactive waste — deuterium can be extracted from seawater, and a fusion reaction stops the instant confinement is lost, so a runaway accident of the Chernobyl or Fukushima type is physically impossible. That combination is why governments continue to fund it despite decades without commercial output. For India, membership of ITER matters beyond the energy question: it gives Indian industry and research institutions access to superconducting magnet, cryogenics and materials technology at a scale the country could not develop alone.
Artificial Sun = experimental reactor recreating solar fusion on earth
Fusion joins light nuclei; fission splits heavy nuclei
Fuel: deuterium and tritium, isotopes of hydrogen
Tokamak = doughnut-shaped magnetic confinement chamber
China's EAST held high-confinement plasma for 1,066 seconds
ITER is in southern France with seven members, India among them
India's Institute for Plasma Research operates the ADITYA and SST-1 tokamaks
It is the popular name for an experimental fusion reactor that heats hydrogen isotopes into a plasma at extreme temperatures to fuse them, reproducing on earth the reaction that powers the Sun.
Fusion joins light nuclei such as deuterium and tritium into a heavier one, while fission splits heavy nuclei such as uranium-235. Fusion produces no long-lived high-level waste and cannot run away, but is far harder to achieve.
A tokamak is a doughnut-shaped reactor chamber surrounded by powerful magnets that confine a plasma in a magnetic field so it never touches the reactor walls.
Yes. India is one of the seven members of ITER, along with the European Union, China, Japan, South Korea, Russia and the United States. India's domestic fusion research is led by the Institute for Plasma Research at Gandhinagar.