China’s EAST reactor keeps the fire of magnetic fusion burning

• Chinese scientists achieved a plasma temperature of 100 million degrees C for 1,066 seconds in the Experimental Advanced Superconducting Tokamak (EAST).

• The process of nuclear fusion, where two atomic nuclei fuse together, is a significant technological goal for clean energy sources.

• The tritium problem is the energy required to start and sustain a fusion reaction. For fusion to occur, the nuclei need to be exposed to a temperature of at least 100 million degrees C.

• Deuterium-deuterium fusion requires a higher temperature to begin than deuteriumtritium fusion due to the extra neutron in the tritium nucleus.

• The fusion of a deuterium and a tritium nucleus creates a non-radioactive helium-4 nucleus, a neutron, and 17.6 MeV of energy.

• The temperature problem is another challenge for nuclear fusion. For two nuclei to fuse, they need to overcome like-charges in the nuclei and come within around 1 femtometre (fm) of each other to bond using the strong nuclear force.

• Different reactor designs, such as the tokamak, are used to achieve nuclear fusion.

• A magnetic cage is used inside the vessel, where a deuterium gas is exposed to about 20 million degrees C and the charged particles are exposed to a strong magnetic field.

• Electromagnets are used to create these fields, which can carry electric current with zero resistance if cooled to a very low temperature.

• The EAST has both toroidal and poloidal magnetic fields generated by superconducting electromagnets, preventing particles from drifting into the vessel’s walls and collapsing the plasma.