Colliding Beam Fusion

Colliding beam fusion, or a colliding beam fusion reactor, is a class of fusion power concepts based on two or more intersecting beams of fusion fuel ions that are independently accelerated to fusion-relevant energies using particle accelerator designs or other similar means, rather than being heated together as a single bulk plasma. The approach traces back to direct-acceleration fusion techniques explored from the 1930s onward, and its technical variants include the inertial electrostatic confinement designs Fusor and Polywell as well as devices such as Migma and the Tri-Alpha Energy design later commercialized as TAE Technologies. A persistent obstacle across colliding beam designs is the ionization drag problem, in which the accelerated ion beams lose energy to collisions with the background plasma faster than they can be replenished, which is a major reason none of the colliding beam approaches has yet achieved net energy gain or commercial viability.