when did plasma become a state of matter
Plasma (physics) Plasma (from Ancient Greek πλάσμα​, meaning 'moldable substance'[1]) is one of the four fundamental states of matter, and was first described by chemist Irving Langmuir[2] in the 1920s.[3] Unlike the other three states, solid, liquid, and gas, plasma does not exist freely on the Earth's surface under normal conditions. Plasma can only be artificially generated by heating or subjecting a neutral gas to a strong electromagnetic field to the point an ionised gaseous substance becomes increasingly electrically conductive, and long-range electromagnetic fields dominate the behavior of the matter.[4]
Fusion power Fusion processes require fuel and a highly confined environment with a high temperature and pressure, to create a plasma in which fusion can occur. In stars, the most common fuel is hydrogen, and gravity creates the high temperature and confinement needed for fusion. Fusion reactors generally use hydrogen isotopes such as deuterium and tritium, which react more easily, and create a confined plasma of millions of degrees using inertial methods (laser) or magnetic methods (tokamak and similar), although many other concepts have been attempted. The major challenges in realising fusion power are to engineer a system that can confine the plasma long enough at high enough temperature and density, for a long term reaction to occur, and for the most common reactions, managing neutrons that are released during the reaction, which over time can degrade many common materials used within the reaction chamber.