Nuclear fusion

fusionhydrogen fusionfusion reactionfusingfusethermonuclear fusionthermonuclearthermonuclear reactionfusesfused
In nuclear chemistry, nuclear fusion is a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles (neutrons or protons).wikipedia
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Main sequence

main-sequencemain sequence dwarfmain-sequence star
Fusion is the process that powers active or "main sequence" stars, or other high magnitude stars.
After condensation and ignition of a star, it generates thermal energy in its dense core region through nuclear fusion of hydrogen into helium.

Triple-alpha process

helium fusionhelium burningtriple alpha process
This means that the lighter elements, such as hydrogen and helium, are in general more fusible; while the heavier elements, such as uranium, thorium and plutonium, are more fissionable.
The triple-alpha process is a set of nuclear fusion reactions by which three helium-4 nuclei (alpha particles) are transformed into carbon.

Nuclear reaction

nuclear reactionsnuclearreaction
In nuclear chemistry, nuclear fusion is a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles (neutrons or protons).
Perhaps the most notable nuclear reactions are the nuclear chain reactions in fissionable materials that produce induced nuclear fission, and the various nuclear fusion reactions of light elements that power the energy production of the Sun and stars.

Supernova

supernovaecore-collapse supernovasupernovas
The extreme astrophysical event of a supernova can produce enough energy to fuse nuclei into elements heavier than iron.
Theoretical studies indicate that most supernovae are triggered by one of two basic mechanisms: the sudden re-ignition of nuclear fusion in a degenerate star or the sudden gravitational collapse of a massive star's core.

Mark Oliphant

Sir Mark OliphantMarcus Laurence Elwin OliphantSir Marcus Laurence Elwin Oliphant
Building on the early experiments in nuclear transmutation by Ernest Rutherford, laboratory fusion of hydrogen isotopes was accomplished by Mark Oliphant in 1932.
Sir Marcus Laurence Elwin "Mark" Oliphant (8 October 1901 – 14 July 2000) was an Australian physicist and humanitarian who played an important role in the first experimental demonstration of nuclear fusion and in the development of nuclear weapons.

Thermonuclear fusion

thermonuclearfusingfusion
Research into developing controlled thermonuclear fusion for civil purposes began in earnest in the 1940s, and it continues to this day.
Thermonuclear fusion is a way to achieve nuclear fusion by using extremely high temperatures.

Ivy Mike

MikeMike test10.4 megaton
Nuclear fusion on a large scale in an explosion was first carried out on November 1, 1952, in the Ivy Mike hydrogen bomb test.
Ivy Mike was the codename given to the first test of a full-scale thermonuclear device, in which part of the explosive yield comes from nuclear fusion.

Nuclear fission

fissionfission reactionfissionable
The opposite is true for the reverse process, nuclear fission.
A similar process occurs in fissionable isotopes (such as uranium-238), but in order to fission, these isotopes require additional energy provided by fast neutrons (such as those produced by nuclear fusion in thermonuclear weapons).

Nuclear chemistry

nuclear chemistnuclear scientistchemistry
In nuclear chemistry, nuclear fusion is a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles (neutrons or protons).
A combination of radiochemistry and radiation chemistry is used to study nuclear reactions such as fission and fusion.

Manhattan Project

atomic bomb projectatomic bombdevelopment of the atomic bomb
Research into fusion for military purposes began in the early 1940s as part of the Manhattan Project.
Edward Teller pushed for discussion of a more powerful bomb: the "super", now usually referred to as a "hydrogen bomb", which would use the explosive force of a detonating fission bomb to ignite a nuclear fusion reaction in deuterium and tritium.

Direct energy conversion

direct conversiondirect conversion to extract energy
Only direct conversion of mass into energy, such as that caused by the annihilatory collision of matter and antimatter, is more energetic per unit of mass than nuclear fusion.
It is a scheme for power extraction from nuclear fusion.

Iron-56

56 Fe
A fusion process that produces a nucleus lighter than iron-56 or nickel-62 will generally yield a net energy release.
Thus, light elements undergoing nuclear fusion and heavy elements undergoing nuclear fission release energy as their nucleons bind more tightly, and the resulting nuclei approach the maximum total energy per nucleon, which occurs at 62 Ni. However, during nucleosynthesis in stars the competition between photodisintegration and alpha capturing causes more 56 Ni to be produced than 62 Ni ( 56 Fe is produced later in the star's ejection shell as 56 Ni decays).

ITER

International Thermonuclear Experimental ReactorInternational Thermonuclear Experimental Reactor (ITER)ITER for fusion energy
Workable designs for a toroidal reactor that theoretically will deliver ten times more fusion energy than the amount needed to heat plasma to the required temperatures are in development (see ITER).
ITER (International Thermonuclear Experimental Reactor) is an international nuclear fusion research and engineering megaproject, which will be the world's largest magnetic confinement plasma physics experiment.

Inertial confinement fusion

laser fusioninertial confinementICF
The US National Ignition Facility, which uses laser-driven inertial confinement fusion, was designed with a goal of break-even fusion; the first large-scale laser target experiments were performed in June 2009 and ignition experiments began in early 2011.
Inertial confinement fusion (ICF) is a type of fusion energy research that attempts to initiate nuclear fusion reactions by heating and compressing a fuel target, typically in the form of a pellet that most often contains a mixture of deuterium and tritium.

National Ignition Facility

NIF
The US National Ignition Facility, which uses laser-driven inertial confinement fusion, was designed with a goal of break-even fusion; the first large-scale laser target experiments were performed in June 2009 and ignition experiments began in early 2011.
NIF uses lasers to heat and compress a small amount of hydrogen fuel with the goal of inducing nuclear fusion reactions.

Energy

energiesenergy transfertotal energy
The difference in mass between the reactants and products is manifested as either the release or absorption of energy.
The nuclear fusion of hydrogen in the Sun also releases another store of potential energy which was created at the time of the Big Bang.

Proton–proton chain reaction

proton-proton chain reactionproton-proton chainproton–proton chain
The primary source of solar energy, and similar size stars, is the fusion of hydrogen to form helium (the proton-proton chain reaction), which occurs at a solar-core temperature of 14 million kelvin.
The proton–proton chain reaction is one of two known sets of nuclear fusion reactions by which stars convert hydrogen to helium.

Strong interaction

strong forcestrongstrong interactions
The strong force grows rapidly once the nuclei are close enough, and the fusing nucleons can essentially "fall" into each other and the result is fusion and net energy produced.
Differences in the binding energy of the nuclear force between different nuclei power nuclear fusion and nuclear fission.

Deuterium

deuterondeuteronsD
For example, the ionization energy gained by adding an electron to a hydrogen nucleus is 13.6 eV—less than one-millionth of the 17.6 MeV released in the deuterium–tritium (D–T) reaction shown in the adjacent diagram.
There is thought to be little deuterium in the interior of the Sun and other stars, as at temperatures there nuclear fusion reactions that consume deuterium happen much faster than the proton-proton reaction that creates deuterium.

Nucleosynthesis

nucleosyntheticnucleogenesissynthesized
Fusion powers stars and produces virtually all elements in a process called nucleosynthesis.
Synthesis of these elements occurred either by nuclear fusion (including both rapid and slow multiple neutron capture) or to a lesser degree by nuclear fission followed by beta decay.

Isotopes of hydrogen

protiumhydrogen-1 1 H
Building on the early experiments in nuclear transmutation by Ernest Rutherford, laboratory fusion of hydrogen isotopes was accomplished by Mark Oliphant in 1932.
Deuterium is also a potential fuel for commercial nuclear fusion.

Astrophysics

astrophysicistastrophysicaltheoretical astrophysics
The extreme astrophysical event of a supernova can produce enough energy to fuse nuclei into elements heavier than iron.
Around 1920, following the discovery of the Hertsprung-Russell diagram still used as the basis for classifying stars and their evolution, Arthur Eddington anticipated the discovery and mechanism of nuclear fusion processes in stars, in his paper The Internal Constitution of the Stars.

CNO cycle

CNOcarbon-nitrogen-oxygen (CNO) cyclecarbon-nitrogen-oxygen cycle
In heavier stars, the CNO cycle and other processes are more important.
The CNO cycle (for carbon–nitrogen–oxygen) is one of the two known sets of fusion reactions by which stars convert hydrogen to helium, the other being the proton–proton chain reaction (pp-chain reaction).

Iron peak

iron-peakvicinity of ironcannot be formed
For larger nuclei, however, no energy is released, since the nuclear force is short-range and cannot continue to act across longer atomic length scales.
For elements lighter than iron on the periodic table, nuclear fusion releases energy while fission consumes it. For iron, and for all of the heavier elements, nuclear fusion consumes energy, but nuclear fission releases it. Chemical elements up to the iron peak are produced in ordinary stellar nucleosynthesis.

Helium

Hesuperfluid heliumhelium II
Francis Aston had also recently shown that the mass of a helium atom was about 0.8% less than the mass of the four hydrogen atoms which would, combined, form a helium atom, suggesting that if such a combination could happen, it would release considerable energy as a byproduct.
This helium-4 binding energy also accounts for why it is a product of both nuclear fusion and radioactive decay.