magnetic confinement fusion

anonymous asked:

Are there different kinds of ways to create fusion?

I’m glad you asked! Right now, there are two major experimental approaches for fusion being studied: magnetic confinement and inertial confinement.

In magnetic confinement fusion, the electrical conductivity of deuterium-tritium plasma is used to contain it within magnetic fields at a high pressure and heated to fusion temperature. Because the particles need to be repelled from the walls of a reactor (otherwise contact will dissipate their heat and slow them down), the most effective magnetic configuration is toroidal wherein the magnetic field is curved around and forms a closed loop. There are several different types of toroidal confinement systems but the most important are tokamaks and stellarators (reversed-field pinch devices would be next; however, plasma confinement in the best RFP is only about 1% as good as in the best tokamaks, owing largely to the fact that existing RFPs are very small).

Tokamak

Stellarator

In inertial confinement fusion, which is a newer line of fusion research, laser or ion beams are focused extremely precisely on a target - a pellet of deuterium-tritium fuel only a few millimeters in diameter. When the outer layer of the material is heated, it creates an outward explosion that generates an implosion that in turn compresses and heats the inner layers of material and results in conditions in which fusion can occur. The core of the fuel may be compressed to 1,000 times its liquid density and the energy released heats the surrounding fuel that may also undergo fusion, leading to a chain reaction (this is referred to as ignition) as the reaction spreads outward through the fuel. 

Large scale attempts at inertial confinement fusion include the Shiva laser built by Lawrence Livermore National Lab, followed by the Nova laser, the 24 beam OMEGA laser and the Novette Laser, which all paved the way for the National Ignition Facility in Livermore, California.