A machine for creating controlled
fusion reactions, where smaller
atoms are combined to create larger
atoms. In creating the
elements up to
iron, energy is liberated in this process. It is hoped that the energy generated by
fusion could be used to generate power. Unfortunately
fusion requires very high
temperatures and pressures, which is why it requires advanced
reactors. All fusion reactors at the moment use either
deuterium and
tritium or just
deuterium as their fuel.
Fusion reactors come in three main types:
Magnetic confinement reactors
Inertial confinement reactors
Cold fusion devices
Magnetic confinement reactors use strong magnetic fields to confine and compress the plasma as it is heated this category consists of tokamaks, stellerators and spherical tokamaks
Inertial confinement reactors, or laser fusion reactors, use a massively powerful array of lasers to heat the outside of a pellet of fusion fuel. The expansion of the outside surface of the pellet caused by the heating compresses the inside of the pellet, allowing it to reach the temperatures and pressures required for fusion.
Cold fusion devices are machines designed to create fusion reactions at room temperature. This type of fusion became infamous after the "discovery" of cold fusion in 1989 by two scientists became a worldwide fiasco, as it became apparent that their discovery was largely fiction. Investigation had effectively ceased into cold fusion, although recent developments in sonoluminescence have re-ignited interest in this avenue of research
None of these types of reactor has managed to create a fusion reactor with a positive energy output, ie. creates more energy than it needs to run. ITER, a planned next-generation fusion reactor, is hoped to be the first to have a positive energy output.