China’s Experimental Advanced Superconducting Tokamak (EAST) or Artificial Sun, kept plasma  stable at extreme densities, previously seen as a major obstacle in nuclear fusion. 

• Researchers believed that plasma could not exceed a certain density without becoming unstable, known as Greenwald limit. 

About Nuclear Fusion

• Process by which two light atomic nuclei combine to form a single heavier one while releasing massive amounts of energy.
• It powers the suns and stars. 
• It occurs in the state of matter called plasma — a hot, charged gas made of positive ions and free-moving electrons with unique properties distinct from solids, liquids or gases.

About Tokamak Reactors

• It is an experimental machine designed to harness the energy of fusion. 
• A fusion plasma is created and confined by strong magnetic fields inside a doughnut shaped chamber.
• The energy produced through fusion of atoms in the plasma is absorbed as heat in the walls of the vessel. 
• Just like a conventional power plant, a fusion power plant will use this heat to produce steam and then electricity by way of turbines and generators.
• International Thermonuclear Energy Reactor (ITER): World's largest tokamak launched as an international joint experiment in fusion, located in Southern France. 
  • Members: 27 members of European Union, China, India, Japan, Korea, Russia, United States and Switzerland.