A stellarator is a device that confines plasma using external magnets. Scientists researching magnetic confinement fusion aim to use stellarator devices as a vessel for nuclear fusion reactions. The name refers to stars as fusion also occurs in stars such as the Sun. It is one of the earliest fusion power devices, along with the z-pinch and magnetic mirror.
A tokamak is a device which uses a powerful magnetic field generated by external magnets to confine plasma in the shape of an axially-symmetrical torus. The tokamak is one of several types of magnetic confinement devices being developed to produce controlled thermonuclear fusion power. The tokamak concept is currently one of the leading candidates for a practical fusion reactor.
Princeton Plasma Physics Laboratory (PPPL) is a United States Department of Energy national laboratory for plasma physics and nuclear fusion science. Its primary mission is research into and development of fusion as an energy source. It is known for the development of the stellarator and tokamak designs, along with numerous fundamental advances in plasma physics and the exploration of many other plasma confinement concepts.
Fusion power is a proposed form of power generation that would generate electricity by using heat from nuclear fusion reactions. In a fusion process, two lighter atomic nuclei combine to form a heavier nucleus, while releasing energy. Devices designed to harness this energy are known as fusion reactors. Research into fusion reactors began in the 1940s, but as of 2024, no device has reached net power, although net positive reactions have been achieved.
This timeline of nuclear fusion is an incomplete chronological summary of significant events in the study and use of nuclear fusion.
ITER is an international nuclear fusion research and engineering megaproject aimed at creating energy through a fusion process similar to that of the Sun. Upon completion of construction of the main reactor and first plasma, planned for 2033–2034, it will be the world's largest magnetic confinement plasma physics experiment and the largest experimental tokamak nuclear fusion reactor. It is being built next to the Cadarache facility in southern France. ITER will be the largest of more than 100 fusion reactors built since the 1950s, with six times the plasma volume of JT-60SA, the largest tokamak operating today.
The Levitated Dipole Experiment (LDX) was an experiment investigating the generation of fusion power using the concept of a levitated dipole. The device was the first of its kind to test the levitated dipole concept and was funded by the US Department of Energy. The machine was also part of a collaboration between the MIT Plasma Science and Fusion Center and Columbia University, where another (non-levitated) dipole experiment, the Collisionless Terrella Experiment (CTX), was located.
The Tokamak Fusion Test Reactor (TFTR) was an experimental tokamak built at Princeton Plasma Physics Laboratory (PPPL) circa 1980 and entering service in 1982. TFTR was designed with the explicit goal of reaching scientific breakeven, the point where the heat being released from the fusion reactions in the plasma is equal or greater than the heating being supplied to the plasma by external devices to warm it up.
Magnetic confinement fusion (MCF) is an approach to generate thermonuclear fusion power that uses magnetic fields to confine fusion fuel in the form of a plasma. Magnetic confinement is one of two major branches of controlled fusion research, along with inertial confinement fusion.
Alcator C-Mod was a tokamak that operated between 1991 and 2016 at the Massachusetts Institute of Technology (MIT) Plasma Science and Fusion Center (PSFC). Notable for its high toroidal magnetic field, Alcator C-Mod holds the world record for volume averaged plasma pressure in a magnetically confined fusion device. Until its shutdown in 2016, it was one of the major fusion research facilities in the United States.
The National Spherical Torus Experiment (NSTX) is a magnetic fusion device based on the spherical tokamak concept. It was constructed by the Princeton Plasma Physics Laboratory (PPPL) in collaboration with the Oak Ridge National Laboratory, Columbia University, and the University of Washington at Seattle. It entered service in 1999. In 2012 it was shut down as part of an upgrade program and became NSTX-U, for Upgrade.
The National Compact Stellarator Experiment, NCSX in short, was a magnetic fusion energy experiment based on the stellarator design being constructed at the Princeton Plasma Physics Laboratory (PPPL).
The Wendelstein 7-X reactor is an experimental stellarator built in Greifswald, Germany, by the Max Planck Institute for Plasma Physics (IPP), and completed in October 2015. Its purpose is to advance stellarator technology: though this experimental reactor will not produce electricity, it is used to evaluate the main components of a future fusion power plant; it was developed based on the predecessor Wendelstein 7-AS experimental reactor.
General Fusion is a Canadian company based in Richmond, British Columbia, which is developing a fusion power technology based on Magnetized Target Fusion (MTF). The company was founded in 2002 by Dr. Michel Laberge. The company has more than 150 employees.
Helion Energy, Inc. is an American fusion research company, located in Everett, Washington. They are developing a magneto-inertial fusion technology to produce helium-3 and fusion power via aneutronic fusion, which could produce low-cost clean electric energy using a fuel that can be derived exclusively from water.
The Model C stellarator was the first large-scale stellarator to be built, during the early stages of fusion power research. Planned since 1952, construction began in 1961 at what is today the Princeton Plasma Physics Laboratory (PPPL). The Model C followed the table-top sized Model A, and a series of Model B machines that refined the stellarator concept and provided the basis for the Model C, which intended to reach break-even conditions. Model C ultimately failed to reach this goal, producing electron temperatures of 400 eV when about 100,000 were needed. In 1969, after UK researchers confirmed that the USSR's T-3 tokamak was reaching 1000 eV, the Model C was converted to the Symmetrical Tokamak, and stellarator development at PPPL ended.
The history of nuclear fusion began early in the 20th century as an inquiry into how stars powered themselves and expanded to incorporate a broad inquiry into the nature of matter and energy, as potential applications expanded to include warfare, energy production and rocket propulsion.
The Tokamak Physics Experiment (TPX) was a plasma physics experiment that was designed but not built. It was designed by an inter-organizational team in the USA led by Princeton Plasma Physics Laboratory. The experiment was designed to test theories about how Tokamaks would behave in a high-performance, steady-state regime.
The Fusion Pilot Plant is a program initiated in 2021 by the United States Department of Energy to construct a pilot plant capable of producing net electrical fusion power by the 2030s. In September 2022, $50 million was earmarked by the Department of Energy for development of a pilot fusion power plant. The National Academies of Sciences, Engineering and Medicine was involved in kicking off the program and advised it become a United States public-private partnership. In the same month, a Funding Opportunity Announcement was released launching the competitive application process for the Fusion Pilot Plant program under the official title of the Milestone-Based Fusion Development Program
Maria Gatu Johnson is a Swedish-American plasma physicist whose research involves the use of neutron spectrometry to study inertial confinement fusion and stellar nucleosynthesis. She works at the Massachusetts Institute of Technology as a principal research scientist in the MIT Plasma Science and Fusion Center.
