Nuclear fusion is a reaction in which two or more atomic nuclei, usually deuterium and tritium, combine to form one or more different atomic nuclei and subatomic particles. The difference in mass between the reactants and products is manifested as either the release or absorption of energy. This difference in mass arises due to the difference in nuclear binding energy between the atomic nuclei before and after the reaction. Nuclear fusion is the process that powers active or main-sequence stars and other high-magnitude stars, where large amounts of energy are released.
A fusion rocket is a theoretical design for a rocket driven by fusion propulsion that could provide efficient and sustained acceleration in space without the need to carry a large fuel supply. The design requires fusion power technology beyond current capabilities, and much larger and more complex rockets.
A fusor is a device that uses an electric field to heat ions to a temperature in which they undergo nuclear fusion. The machine induces a potential difference between two metal cages, inside a vacuum. Positive ions fall down this voltage drop, building up speed. If they collide in the center, they can fuse. This is one kind of an inertial electrostatic confinement device – a branch of fusion research.
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.
A neutron source is any device that emits neutrons, irrespective of the mechanism used to produce the neutrons. Neutron sources are used in physics, engineering, medicine, nuclear weapons, petroleum exploration, biology, chemistry, and nuclear power.
This timeline of nuclear fusion is an incomplete chronological summary of significant events in the study and use of nuclear fusion.
Robert W. Bussard was an American physicist who worked primarily in nuclear fusion energy research. He was the recipient of the Schreiber-Spence Achievement Award for STAIF-2004. He was also a fellow of the International Academy of Astronautics and held a Ph.D. from Princeton University.
Inertial electrostatic confinement, or IEC, is a class of fusion power devices that use electric fields to confine the plasma rather than the more common approach using magnetic fields found in magnetic confinement fusion (MCF) designs. Most IEC devices directly accelerate their fuel to fusion conditions, thereby avoiding energy losses seen during the longer heating stages of MCF devices. In theory, this makes them more suitable for using alternative aneutronic fusion fuels, which offer a number of major practical benefits and makes IEC devices one of the more widely studied approaches to fusion.
Neutron generators are neutron source devices which contain compact linear particle accelerators and that produce neutrons by fusing isotopes of hydrogen together. The fusion reactions take place in these devices by accelerating either deuterium, tritium, or a mixture of these two isotopes into a metal hydride target which also contains deuterium, tritium or a mixture of these isotopes. Fusion of deuterium atoms results in the formation of a helium-3 ion and a neutron with a kinetic energy of approximately 2.5 MeV. Fusion of a deuterium and a tritium atom results in the formation of a helium-4 ion and a neutron with a kinetic energy of approximately 14.1 MeV. Neutron generators have applications in medicine, security, and materials analysis.
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.
Aneutronic fusion is any form of fusion power in which very little of the energy released is carried by neutrons. While the lowest-threshold nuclear fusion reactions release up to 80% of their energy in the form of neutrons, aneutronic reactions release energy in the form of charged particles, typically protons or alpha particles. Successful aneutronic fusion would greatly reduce problems associated with neutron radiation such as damaging ionizing radiation, neutron activation, reactor maintenance, and requirements for biological shielding, remote handling and safety.
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.
DEMO, or a demonstration power plant, refers to a proposed class of nuclear fusion experimental reactors that are intended to demonstrate the net production of electric power from nuclear fusion. Most of the ITER partners have plans for their own DEMO-class reactors. With the possible exception of the EU and Japan, there are no plans for international collaboration as there was with ITER.
The polywell is a proposed design for a fusion reactor using an electric and magnetic field to heat ions to fusion conditions.
Magnetized Target Fusion (MTF) is a fusion power concept that combines features of magnetic confinement fusion (MCF) and inertial confinement fusion (ICF). Like the magnetic approach, the fusion fuel is confined at lower density by magnetic fields while it is heated into a plasma. As with the inertial approach, fusion is initiated by rapidly squeezing the target to greatly increase fuel density and temperature. Although the resulting density is far lower than in ICF, it is thought that the combination of longer confinement times and better heat retention will let MTF operate, yet be easier to build. The term magneto-inertial fusion (MIF) is similar, but encompasses a wider variety of arrangements. The two terms are often applied interchangeably to experiments.
Thiago David Olson is a venture capitalist, electrical engineer and entrepreneur. Olson is the co-founder and CEO of Stratos Technologies, Inc., creators of the Stratos Card. As an electrical engineer Olson became known as a teenager for his research in Nuclear Fusion and Neutron Sciences. As a 17-year-old, attending Stoney Creek High School in Rochester Hills, Michigan, Olson created a homemade nuclear fusion reactor. In his article Neutron activation analysis using an inertial electrostatic confinement fusion device he indicated that his apparatus did not produce surplus energy.
The Lockheed Martin Compact Fusion Reactor (CFR) was a fusion power project at Lockheed Martin’s Skunk Works. Its high-beta configuration, which implies that the ratio of plasma pressure to magnetic pressure is greater than or equal to 1, allows a compact design and expedited development. The project was active between 2010 and 2019, after that date there have been no updates and it appears the division has shut down.
Colliding beam fusion (CBF), or colliding beam fusion reactor (CBFR), is a class of fusion power concepts that are based on two or more intersecting beams of fusion fuel ions that are independently accelerated to fusion energies using a variety of particle accelerator designs or other means. One of the beams may be replaced by a static target, in which case the approach is termed accelerator based fusion or beam-target fusion, but the physics is the same as colliding beams.
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.
Lattice confinement fusion (LCF) is a type of nuclear fusion in which deuteron-saturated metals are exposed to gamma radiation or ion beams, such as in an IEC fusor, avoiding the confined high-temperature plasmas used in other methods of fusion.
