Matter-Antimatter Annihilation involved direct annihilation of equal amounts of matter and antimatter. This provided a lot of energy.
(Note: The background section of this page uses most of the same words as the antimatter-induced fusion page of Terra Futura to save time.)
Paul Dirac first proposed the existence of antimatter in 1928. He was not confirmed until 1932 when physicist Carl David Anderson discovered the positron, the antimatter equivalent of the electron. Then, in the 1950s, the antiproton and the antineutron were discovered. This was followed by the discovery of antinuclei in 1965. The path to antiatoms was opened. In 1995, antihydrogen was discovered. This was followed in 2011 by the discovery of antihelium. However, antimatter was expensive. But in the early-to-mid-21st century, advances in technology allowed antimatter power stations to be built for the first time.
Antimatter injection was the simplest method of antimatter power in use. In this process, antiprotons were injected into a working medium like liquid hydrogen. Enough antiprotons could turn the liquid into a gas. This would turn turbines to produce electricity. If there enough antimatter, the liquid could become a plasma. This was useful for space propulsion like in the science fiction franchise Star Trek. Antimatter was still expensive, so antimatter injection was used only in certain applications. One of these was in space. Even so, there was an even bigger problem. Antimatter could not be contained in a conventional container. The solution was advanced antimatter traps. Advances in magnetic fields in the 21st century led to advanced antimatter Penning traps. These traps were better more compact, and more efficient. Advanced particle cooling techniques and more efficient portable energy sources allowed the unit to work longer. This made antimatter easier to use, but it was still expensive. Advances in the use of antimatter led to antimatter-induced fusion.
Antimatter-induced Fusion involved a Penning trap. This Penning trap was full of antiprotons. When a pellet of fission/fusion fuel was sent into the trap, annihilation began. This triggered a fission reaction that sparked a fusion burn in the fuel which was compressed. This created a super-heated plasma which generated power. After each burn, the Penning trap would be reset back to its original configuration. After 50 burns, new antiprotons would be put in. This was still expensive, but it was used in many space-based applications. As time went on, antimatter-induced fusion was replaced with matter-antimatter annihilation.
Tech Level: 13
By the late 22nd century, energy demand had risen so high that nuclear fusion was not enough for the needs of the humans. By now, new power plants were coming online that used matter-antimatter annihilation. They were one thousand times more powerful than fission reactors and 300 times more powerful than fusion reactors. The main problem was that the reaction had to be kept steady. Otherwise, the reactor would shut down. The reactants were contained in a magnetic field that was pulsed millions of times to keep the reactor steady. There was more problem. Where did the antimatter come from? The solution was antimatter factories.