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The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing sustainable fusion power. From the top: 1. the deuterium (2D) and tritium (3T) nuclei are accelerated towards each other at thermonuclear speeds/temperatures; 2. they combine to create an unstable helium-5 (5He) nucleus; 3. the 5He nucleus decays, resulting in the ejection of a neutron and repulsion of the remaining Helium-4 (4He) nucleus, both with high energies.
The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing sustainable fusion power. Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen. Fusion power is power generated by Nuclear fusion reactions In this kind of reaction two light atomic nuclei fuse From the top: 1. the deuterium (2D) and tritium (3T) nuclei are accelerated towards each other at thermonuclear speeds/temperatures; 2. Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen. they combine to create an unstable helium-5 (5He) nucleus; 3. Although there are eight known Isotopes of Helium ( He) (standard atomic mass 4 the 5He nucleus decays, resulting in the ejection of a neutron and repulsion of the remaining Helium-4 (4He) nucleus, both with high energies. Although there are eight known Isotopes of Helium ( He) (standard atomic mass 4 This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. Helium-4 ( or) is a non- Radioactive and light Isotope of Helium.
For the generation of electrical power by fusion, see Fusion power. Fusion power is power generated by Nuclear fusion reactions In this kind of reaction two light atomic nuclei fuse For military applications of fusion, see Teller-Ulam design. The Teller–Ulam design is a Nuclear weapon design which is used in Megaton -range Thermonuclear weapons and is more colloquially referred to as "the

In physics and nuclear chemistry, nuclear fusion is the process by which multiple atomic particles join together to form a heavier nucleus. Physics (Greek Physis - φύσις in everyday terms is the Science of Matter and its motion. Nuclear chemistry is a subfield of Chemistry dealing with Radioactivity, nuclear processes and nuclear properties It is accompanied by the release or absorption of energy. In Physics and other Sciences energy (from the Greek grc ἐνέργεια - Energeia, "activity operation" from grc ἐνεργός Iron and nickel nuclei have the largest binding energies per nucleon of all nuclei. Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Nickel (ˈnɪkəl is a metallic Chemical element with the symbol Ni and Atomic number 28 Binding energy is the Mechanical energy required to disassemble a whole into separate parts The fusion of two nuclei lighter than iron generally releases energy while the fusion of nuclei heavier than iron absorbs energy; vice-versa for the reverse process, nuclear fission. Nuclear fission is the splitting of the nucleus of an atom into parts (lighter nuclei) often producing Free neutrons and other smaller nuclei which may

Nuclear fusion occurs naturally in stars. Artificial fusion in human enterprises has also been achieved, although not yet completely controlled. Building upon the nuclear transmutation experiments of Ernest Rutherford done a few years earlier, fusion of light nuclei (hydrogen isotopes) was first observed by Mark Oliphant in 1932, and the steps of the main cycle of nuclear fusion in stars were subsequently worked out by Hans Bethe throughout the remainder of that decade. Nuclear transmutation is the conversion of one Chemical element or Isotope into another which occurs through Nuclear reactions Natural transmutation occurs Ernest Rutherford 1st Baron Rutherford of Nelson, OM, PC, FRS (30 August 1871 – 19 October 1937 was a New Zealand Physicist Sir Marcus 'Mark' Laurence Elwin Oliphant AC, KBE ( October 8 1901 &ndash July 14, 2000) was an Australian Hans Albrecht Bethe (/hans ˈalbʀɛçt ˈbeːtə/ ( July 2 1906 &ndash March 6, 2005) was a German - American Physicist Research into fusion for military purposes began in the early 1940s, as part of the Manhattan Project, but was not successful until 1952. The World War II Manhattan Project developed the first Nuclear weapon (atomic bomb Research into controlled fusion for civilian purposes began in the 1950s, and continues to this day.

Contents

Overview

Nuclear physics
Radioactive decay
Nuclear fission
Nuclear fusion
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Fusion reactions power the stars and produce all but the lightest elements in a process called nucleosynthesis. Nuclear physics is the field of Physics that studies the building blocks and interactions of Atomic nuclei. Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. Nuclear fission is the splitting of the nucleus of an atom into parts (lighter nuclei) often producing Free neutrons and other smaller nuclei which may A star is a massive luminous ball of plasma. The nearest star to Earth is the Sun, which is the source of most of the Energy on Earth Nucleosynthesis is the process of creating new atomic nuclei from preexisting Nucleons (protons and neutrons While the fusion of lighter elements in stars releases energy, production of the heavier elements absorbs energy.

When the fusion reaction is a sustained uncontrolled chain, it can result in a thermonuclear explosion, such as that generated by a hydrogen bomb. The energy released from a nuclear weapon detonated in the Troposphere can be divided into four basic categories Blast &mdash40-50% of total energy The Teller–Ulam design is a Nuclear weapon design which is used in Megaton -range Thermonuclear weapons and is more colloquially referred to as "the Reactions which are not self-sustaining can still release considerable energy, as well as large numbers of neutrons. This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron.

Research into controlled fusion, with the aim of producing fusion power for the production of electricity, has been conducted for over 50 years. Fusion power is power generated by Nuclear fusion reactions In this kind of reaction two light atomic nuclei fuse It has been accompanied by extreme scientific and technological difficulties, but resulted in steady progress. As of the present, break-even (self-sustaining) controlled fusion reaction have been demonstrated in a few tokamak-type reactors around the world and resulted in producing workable design of the reactor which will deliver ten times more fusion energy than the amount of energy needed to heat up its plasma to required temperatures (see ITER which is scheduled to be operational in 2016). A tokamak is a machine producing a toroidal Magnetic field for confining a plasma. ITER is an international Tokamak ( Magnetic confinement fusion) research/engineering proposal for an experimental project that will help to make the transition from

It takes considerable energy to force nuclei to fuse, even those of the lightest element, hydrogen. Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 This is because all nuclei have a positive charge (due to their protons), and as like charges repel, nuclei strongly resist being put too close together. Accelerated to high speeds (that is, heated to thermonuclear temperatures), they can overcome this electromagnetic repulsion and get close enough for the attractive nuclear force to be sufficiently strong to achieve fusion. The nuclear force (or nucleon-nucleon interaction or residual strong force) is the force between two or more Nucleons It is responsible for The fusion of lighter nuclei, creating a heavier nucleus and a free neutron, will generally release more energy than it took to force them together-an exothermic process that can produce self-sustaining reactions. A free neutron is a Neutron that exists outside of an Atomic nucleus. An exothermic reaction is a Chemical reaction that releases Heat.

The energy released in most nuclear reactions is much larger than that in chemical reactions, because the binding energy that holds a nucleus together is far greater than the energy that holds electrons to a nucleus. In Nuclear physics, a nuclear reaction is the process in which two nuclei or nuclear particles collide to produce products different from the initial particles A chemical reaction is a process that always results in the interconversion of Chemical substances The substance or substances initially involved in a chemical reaction are called Binding energy is the Mechanical energy required to disassemble a whole into separate parts The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J For example, the ionization energy gained by adding an electron to a hydrogen nucleus is 13.6 electron volts - less than one-millionth of the 17 MeV released in the D-T (deuterium-tritium) reaction shown to the top right. The ionization potential, ionization energy or EI of an Atom or Molecule is the Energy required to remove an Electron This list compares various energies in Joules (J organized by Order of magnitude. This list compares various energies in Joules (J organized by Order of magnitude. Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen. Fusion reactions have an energy density many times greater than nuclear fission-that is, per unit of mass the reactions produce far greater energies, even though individual fission reactions are generally much more energetic than individual fusion reactions-which are themselves millions of times more energetic than chemical reactions. Energy density is the amount of Energy stored in a given system or region of space per unit Volume, or per unit Mass, depending on the context although Nuclear fission is the splitting of the nucleus of an atom into parts (lighter nuclei) often producing Free neutrons and other smaller nuclei which may Only the direct conversion of mass into energy, such as with collision of matter and antimatter, is more energetic per unit of mass than nuclear fusion. In Physics, mass–energy equivalence is the concept that for particles slower than light any Mass has an associated Energy and vice versa. In Particle physics and Quantum chemistry, antimatter is the extension of the concept of the Antiparticle to Matter, where antimatter is composed

Requirements

A substantial energy barrier must be overcome before fusion can occur. At large distances two naked nuclei repel one another because of the repulsive electrostatic force between their positively charged protons. ---- Bold text Coulomb's law', developed in the 1780s by French physicist Charles Augustin de Coulomb, may be stated in scalar form Electric charge is a fundamental conserved property of some Subatomic particles which determines their Electromagnetic interaction. If two nuclei can be brought close enough together, however, the electrostatic repulsion can be overcome by the attractive nuclear force which is stronger at close distances. The nuclear force (or nucleon-nucleon interaction or residual strong force) is the force between two or more Nucleons It is responsible for

When a nucleon such as a proton or neutron is added to a nucleus, the nuclear force attracts it to other nucleons, but primarily to its immediate neighbors due to the short range of the force. In Physics a nucleon is a collective name for two Baryons the Neutron and the Proton. The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. The nucleons in the interior of a nucleus have more neighboring nucleons than those on the surface. Since smaller nuclei have a larger surface area-to-volume ratio, the binding energy per nucleon due to the strong force generally increases with the size of the nucleus but approaches a limiting value corresponding to that of a fully surrounded nucleon.

The electrostatic force, on the other hand, is an inverse-square force, so a proton added to a nucleus will feel an electrostatic repulsion from all the other protons in the nucleus. The electrostatic energy per nucleon due to the electrostatic force thus increases without limit as nuclei get larger.

The electrostatic force caused by positively charged nuclei is very strong over long distances, but at short distances the nuclear force is stronger. As such, the main technical difficulty for fusion is getting the nuclei close enough to fuse. Distances not to scale.
The electrostatic force caused by positively charged nuclei is very strong over long distances, but at short distances the nuclear force is stronger. ---- Bold text Coulomb's law', developed in the 1780s by French physicist Charles Augustin de Coulomb, may be stated in scalar form The nuclear force (or nucleon-nucleon interaction or residual strong force) is the force between two or more Nucleons It is responsible for As such, the main technical difficulty for fusion is getting the nuclei close enough to fuse. Distances not to scale.

The net result of these opposing forces is that the binding energy per nucleon generally increases with increasing size, up to the elements iron and nickel, and then decreases for heavier nuclei. Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Nickel (ˈnɪkəl is a metallic Chemical element with the symbol Ni and Atomic number 28 Eventually, the binding energy becomes negative and very heavy nuclei are not stable. The four most tightly bound nuclei, in decreasing order of binding energy, are 62Ni, 58Fe, 56Fe, and 60Ni. Nickel-62 is an Isotope of Nickel with 28 Protons and 34 Neutrons It is a Stable isotope, and in fact has the highest Nuclear Naturally occurring Iron ( Fe) consists of four Isotopes 5845% of radioactive 54Fe (half-life >3 Iron-56 is the most common Isotope of Iron. About 91754% of all iron is iron-56 Naturally occurring Nickel ( Ni) is composed of 5 stable Isotopes 58Ni 60Ni 61Ni 62Ni and 64Ni [1] Even though the nickel isotope ,62Ni, is more stable, the iron isotope 56Fe is an order of magnitude more common. Naturally occurring Nickel ( Ni) is composed of 5 stable Isotopes 58Ni 60Ni 61Ni 62Ni and 64Ni Naturally occurring Iron ( Fe) consists of four Isotopes 5845% of radioactive 54Fe (half-life >3 An order of magnitude is the class of scale or magnitude of any amount where each class contains values of a fixed ratio to the class preceding it This is due to a greater disintegration rate for 62Ni in the interior of stars driven by photon absorption.

A notable exception to this general trend is the helium-4 nucleus, whose binding energy is higher than that of lithium, the next heavier element. Helium ( He) is a colorless odorless tasteless non-toxic Inert Monatomic Chemical Lithium (ˈlɪθiəm is a Chemical element with the symbol Li and Atomic number 3 The Pauli exclusion principle provides an explanation for this exceptional behavior—it says that because protons and neutrons are fermions, they cannot exist in exactly the same state. The Pauli exclusion principle is a quantum mechanical principle formulated by Wolfgang Pauli in 1925 In Particle physics, fermions are particles which obey Fermi-Dirac statistics; they are named after Enrico Fermi. Each proton or neutron energy state in a nucleus can accommodate both a spin up particle and a spin down particle. Helium-4 has an anomalously large binding energy because its nucleus consists of two protons and two neutrons; so all four of its nucleons can be in the ground state. Any additional nucleons would have to go into higher energy states.

The situation is similar if two nuclei are brought together. As they approach each other, all the protons in one nucleus repel all the protons in the other. Not until the two nuclei actually come in contact can the strong nuclear force take over. The nuclear force (or nucleon-nucleon interaction or residual strong force) is the force between two or more Nucleons It is responsible for Consequently, even when the final energy state is lower, there is a large energy barrier that must first be overcome. It is called the Coulomb barrier. The Coulomb barrier, named after physicist Charles-Augustin de Coulomb (1736&ndash1806 is the energy barrier due to Electrostatic interaction that two nuclei need

The Coulomb barrier is smallest for isotopes of hydrogen—they contain only a single positive charge in the nucleus. A bi-proton is not stable, so neutrons must also be involved, ideally in such a way that a helium nucleus, with its extremely tight binding, is one of the products.

Using deuterium-tritium fuel, the resulting energy barrier is about 0. 01 MeV. In comparison, the energy needed to remove an electron from hydrogen is 13. The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 6 eV, about 750 times less energy. The (intermediate) result of the fusion is an unstable 5He nucleus, which immediately ejects a neutron with 14. 1 MeV. The recoil energy of the remaining 4He nucleus is 3. 5 MeV, so the total energy liberated is 17. 6 MeV. This is many times more than what was needed to overcome the energy barrier.

If the energy to initiate the reaction comes from accelerating one of the nuclei, the process is called beam-target fusion; if both nuclei are accelerated, it is beam-beam fusion. If the nuclei are part of a plasma near thermal equilibrium, one speaks of thermonuclear fusion. In Physics and Chemistry, plasma is an Ionized Gas, in which a certain proportion of Electrons are free rather than being bound Temperature is a measure of the average kinetic energy of particles, so by heating the nuclei they will gain energy and eventually have enough to overcome this 0. The kinetic energy of an object is the extra Energy which it possesses due to its motion 01 MeV. Converting the units between electronvolts and kelvins shows that the barrier would be overcome at a temperature in excess of 120 million kelvins, obviously a very high temperature.

There are two effects that lower the actual temperature needed. One is the fact that temperature is the average kinetic energy, implying that some nuclei at this temperature would actually have much higher energy than 0. Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature 01 MeV, while others would be much lower. It is the nuclei in the high-energy tail of the velocity distribution that account for most of the fusion reactions. This article describes the distribution function as used in physics The other effect is quantum tunneling. In Quantum mechanics, quantum tunnelling is a nanoscopic phenomenon in which a particle violates the principles of Classical mechanics by penetrating a The nuclei do not actually have to have enough energy to overcome the Coulomb barrier completely. If they have nearly enough energy, they can tunnel through the remaining barrier. For this reason fuel at lower temperatures will still undergo fusion events, at a lower rate.

The fusion reaction rate increases rapidly with temperature until it maximizes and then gradually drops off. The DT rate peaks at a lower temperature (about 70 keV, or 800 million kelvins) and at a higher value than other reactions commonly considered for fusion energy.
The fusion reaction rate increases rapidly with temperature until it maximizes and then gradually drops off. The DT rate peaks at a lower temperature (about 70 keV, or 800 million kelvins) and at a higher value than other reactions commonly considered for fusion energy.

The reaction cross section σ is a measure of the probability of a fusion reaction as a function of the relative velocity of the two reactant nuclei. In nuclear and Particle physics, the concept of a cross section is used to express the likelihood of interaction between particles If the reactants have a distribution of velocities, e. g. a thermal distribution with thermonuclear fusion, then it is useful to perform an average over the distributions of the product of cross section and velocity. The reaction rate (fusions per volume per time) is <σv> times the product of the reactant number densities:

f = n_1 n_2 \langle \sigma v \rangle.

If a species of nuclei is reacting with itself, such as the DD reaction, then the product n1n2 must be replaced by (1 / 2)n2.

\langle \sigma v \rangle increases from virtually zero at room temperatures up to meaningful magnitudes at temperatures of 10 – 100 keV. This list compares various energies in Joules (J organized by Order of magnitude. This list compares various energies in Joules (J organized by Order of magnitude. At these temperatures, well above typical ionization energies (13. An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge 6 eV in the hydrogen case), the fusion reactants exist in a plasma state. In Physics and Chemistry, plasma is an Ionized Gas, in which a certain proportion of Electrons are free rather than being bound

The significance of <σv> as a function of temperature in a device with a particular energy confinement time is found by considering the Lawson criterion. In Nuclear fusion research the Lawson criterion, first derived by John D In Nuclear fusion research the Lawson criterion, first derived by John D

Gravitational confinement

One force capable of confining the fuel well enough to satisfy the Lawson criterion is gravity. In Nuclear fusion research the Lawson criterion, first derived by John D Gravitation is a natural Phenomenon by which objects with Mass attract one another The mass needed, however, is so great that gravitational confinement is only found in stars (the smallest of which are brown dwarfs). A star is a massive luminous ball of plasma. The nearest star to Earth is the Sun, which is the source of most of the Energy on Earth Brown dwarfs are sub- stellar objects with a mass below that necessary to maintain Hydrogen -burning Nuclear fusion reactions in their cores as do stars Even if the more reactive fuel deuterium were used, a mass greater than that of the planet Jupiter would be needed.

Magnetic confinement

See Magnetic confinement fusion for more information. Magnetic confinement fusion is an approach to generating Fusion energy that uses Magnetic fields to confine the fusion fuel in the form of a plasma.

The charged ions of fusion fuel follow spiral orbits around magnetic field lines (see Guiding center#Gyration), and the fuel is therefore trapped along the field lines. In Physics, a magnetic field is a Vector field that permeates space and which can exert a magnetic force on moving Electric charges In many cases of practical interest the motion in a Magnetic field of an electrically charged particle (such as an Electron or Ion in a plasma A variety of magnetic configurations exist, including the toroidal geometries of tokamaks and stellarators and open ended mirror confinement systems. A tokamak is a machine producing a toroidal Magnetic field for confining a plasma. A stellarator is a device used to confine a hot plasma with magnetic fields in order to sustain a controlled Nuclear fusion reaction A magnetic mirror is a Magnetic field configuration where the field strength changes when moving along a field line

Inertial confinement

See Inertial fusion energy for more information. Inertial confinement fusion ( ICF) is a process where Nuclear fusion reactions are initiated by heating and compressing a fuel target typically in the form of

A third confinement principle is to apply a rapid pulse of energy to a large part of the surface of a pellet of fusion fuel, causing it to simultaneously "implode" and heat to very high pressure and temperature. If the fuel is dense enough and hot enough, the fusion reaction rate will be high enough to burn a significant fraction of the fuel before it has dissipated. To achieve these extreme conditions, the initially cold fuel must be explosively compressed. Inertial confinement is used in the hydrogen bomb, where the driver is x-rays created by a fission bomb. The Teller–Ulam design is a Nuclear weapon design which is used in Megaton -range Thermonuclear weapons and is more colloquially referred to as "the X-radiation (composed of X-rays) is a form of Electromagnetic radiation. Inertial confinement is also attempted in "controlled" nuclear fusion, where the driver is a laser, ion, or electron beam, or a Z-pinch. A laser is a device that emits Light ( Electromagnetic radiation) through a process called Stimulated emission. An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J In Fusion power research the Z-pinch, or zeta pinch, is a type of plasma confinement system that uses an electrical current in the plasma to generate

Some confinement principles have been investigated, such as muon-catalyzed fusion, the Farnsworth-Hirsch fusor and Polywell (inertial electrostatic confinement), and bubble fusion. Muon-catalyzed fusion ( μCF) is a process allowing Nuclear fusion to take place at Temperatures significantly lower than the temperatures required for The Farnsworth–Hirsch Fusor, or simply fusor, is an apparatus designed by Philo T The polywell is a plasma confinement concept that combines elements of Inertial electrostatic confinement and Magnetic confinement fusion, intended Inertial electrostatic confinement (often abbreviated as IEC) is a concept for retaining a plasma using an electrostatic field Bubble fusion, also known as sonofusion, is the non-technical name for a Nuclear fusion reaction hypothesized to occur during Sonoluminescence, an extreme

Production methods

A variety of methods are known to affect nuclear fusion. Some are "cold" in the strict sense that no part of the material is hot (except for the reaction products), some are "cold" in the limited sense that the bulk of the material is at a relatively low temperature and pressure but the reactants are not, and some are "hot" fusion methods that create macroscopic regions of very high temperature and pressure.

Locally cold fusion

Generally cold, locally hot fusion

Hot fusion

In "standard" "hot" fusion, the fuel reaches tremendous temperature and pressure inside a fusion reactor or nuclear weapon. Fusion power is power generated by Nuclear fusion reactions In this kind of reaction two light atomic nuclei fuse Fusion power is power generated by Nuclear fusion reactions In this kind of reaction two light atomic nuclei fuse A nuclear weapon is an explosive device that derives its destructive force from Nuclear reactions either fission or a combination of fission and fusion.

The methods in the second group are examples of non-equilibrium systems, in which very high temperatures and pressures are produced in a relatively small region adjacent to material of much lower temperature. In his doctoral thesis for MIT, Todd Rider did a theoretical study of all quasineutral, isotropic, non-equilibrium fusion systems. He demonstrated that all such systems will leak energy at a rapid rate due to bremsstrahlung radiation produced when electrons in the plasma hit other electrons or ions at a cooler temperature and suddenly decelerate. Bremsstrahlung ( pronounced, from German de ''bremsen'' "to brake" and de ''Strahlung'' "radiation" i The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J In Physics and Chemistry, plasma is an Ionized Gas, in which a certain proportion of Electrons are free rather than being bound An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge The problem is not as pronounced in a hot plasma because the range of temperatures, and thus the magnitude of the deceleration, is much lower. Note that Rider's work does not apply to non-neutral and/or anisotropic non-equilibrium plasmas.

Important reactions

Astrophysical reaction chains

The proton-proton chain dominates in stars the size of the Sun or smaller.
The proton-proton chain dominates in stars the size of the Sun or smaller. The proton-proton chain reaction is one of several fusion reactions by which Stars convert Hydrogen to Helium, the primary alternative being the
The CNO cycle dominates in stars heavier than the Sun.
The CNO cycle dominates in stars heavier than the Sun. The CNO cycle (for Carbon - Nitrogen - Oxygen) or sometimes Bethe-Weizsäcker-cycle, is one of two sets of fusion reactions

The most important fusion process in nature is that which powers the stars. The net result is the fusion of four protons into one alpha particle, with the release of two positrons, two neutrinos (which changes two of the protons into neutrons), and energy, but several individual reactions are involved, depending on the mass of the star. The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive Alpha particles (named after and denoted by the first letter in the Greek alphabet, α consist of two Protons and two Neutrons bound together into a The positrons or antielectron is the Antiparticle or the Antimatter counterpart of the Electron. Neutrinos are Elementary particles that travel close to the Speed of light, lack an Electric charge, are able to pass through ordinary matter almost For stars the size of the sun or smaller, the proton-proton chain dominates. The proton-proton chain reaction is one of several fusion reactions by which Stars convert Hydrogen to Helium, the primary alternative being the In heavier stars, the CNO cycle is more important. The CNO cycle (for Carbon - Nitrogen - Oxygen) or sometimes Bethe-Weizsäcker-cycle, is one of two sets of fusion reactions Both types of processes are responsible for the creation of new elements as part of stellar nucleosynthesis. Stellar nucleosynthesis is the collective term for the nuclear reactions taking place in Stars to build the nuclei of the heavier elements.

At the temperatures and densities in stellar cores the rates of fusion reactions are notoriously slow. For example, at solar core temperature (T ≈ 15 MK) and density (160 g/cm³), the energy release rate is only 276 μW/cm³—about a quarter of the volumetric rate at which a resting human body generates heat. [8] Thus, reproduction of stellar core conditions in a lab for nuclear fusion power production is completely impractical. Because nuclear reaction rates strongly depend on temperature (exp(−E/kT)), then in order to achieve reasonable rates of energy production in terrestrial fusion reactors 10–100 times higher temperatures (compared to stellar interiors) are required T ≈ 0. 1–1. 0 GK.

Criteria and candidates for terrestrial reactions

In man-made fusion, the primary fuel is not constrained to be protons and higher temperatures can be used, so reactions with larger cross-sections are chosen. This implies a lower Lawson criterion, and therefore less startup effort. In Nuclear fusion research the Lawson criterion, first derived by John D Another concern is the production of neutrons, which activate the reactor structure radiologically, but also have the advantages of allowing volumetric extraction of the fusion energy and tritium breeding. Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen. Reactions that release no neutrons are referred to as aneutronic. Aneutronic fusion is any form of Fusion power where no more than 1% of the total energy released is carried by Neutrons Since the most-studied fusion reactions

In order to be useful as a source of energy, a fusion reaction must satisfy several criteria. It must

Few reactions meet these criteria. The following are those with the largest cross sections:

(1)  21D  +  31T  →  42He  (  3. Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen. Helium-4 ( or) is a non- Radioactive and light Isotope of Helium. 5 MeV  )  +  n0  (  14. This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. 1 MeV  )
(2i)  21D  +  21D  →  31T  (  1. Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen. 01 MeV  )  +  p+  (  3. The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive 02 MeV  )            50%
(2ii)        →  32He  (  0. This article is about the elemental isotope For the record label Helium 3 see Muse or A&E Records. 82 MeV  )  +  n0  (  2. This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. 45 MeV  )            50%
(3)  21D  +  32He  →  42He  (  3. Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth This article is about the elemental isotope For the record label Helium 3 see Muse or A&E Records. Helium-4 ( or) is a non- Radioactive and light Isotope of Helium. 6 MeV  )  +  p+  (  14. The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive 7 MeV  )
(4)  31T  +  31T  →  42He        +  2 n0            +  11. Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen. Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen. Helium-4 ( or) is a non- Radioactive and light Isotope of Helium. This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. 3 MeV
(5)  32He  +  32He  →  42He        +  2 p+            +  12. This article is about the elemental isotope For the record label Helium 3 see Muse or A&E Records. This article is about the elemental isotope For the record label Helium 3 see Muse or A&E Records. Helium-4 ( or) is a non- Radioactive and light Isotope of Helium. The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive 9 MeV
(6i)  32He  +  31T  →  42He        +  p+  +  n0        +  12. This article is about the elemental isotope For the record label Helium 3 see Muse or A&E Records. Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen. Helium-4 ( or) is a non- Radioactive and light Isotope of Helium. The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. 1 MeV    51%
(6ii)        →  42He  (  4. Helium-4 ( or) is a non- Radioactive and light Isotope of Helium. 8 MeV  )  +  21D  (  9. Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth 5 MeV  )            43%
(6iii)        →  42He  (  0. Helium-4 ( or) is a non- Radioactive and light Isotope of Helium. 5 MeV  )  +  n0  (  1. This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. 9 MeV  )  +  p+  (  11. The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive 9 MeV  )  6%
(7i)  21D  +  63Li  →  2 42He  +  22. Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth Naturally occurring Lithium ( Li) (standard atomic mass 6941(2 u) is composed of two stable Isotopes ( and, the latter being the more abundant Helium-4 ( or) is a non- Radioactive and light Isotope of Helium. 4 MeV
(7ii)        →  32He  +  42He    +  n0            +  2. This article is about the elemental isotope For the record label Helium 3 see Muse or A&E Records. Helium-4 ( or) is a non- Radioactive and light Isotope of Helium. This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. 56 MeV
(7iii)        →  73Li  +  p+                  +  5. Naturally occurring Lithium ( Li) (standard atomic mass 6941(2 u) is composed of two stable Isotopes ( and, the latter being the more abundant The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive 0 MeV
(7iv)        →  74Be  +  n0                  +  3. Although Beryllium ( Be) has multiple Isotopes, only one of these isotopes is stable as such it is considered a monoisotopic element This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. 4 MeV
(8)  p+  +  63Li  →  42He  (  1. The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive Naturally occurring Lithium ( Li) (standard atomic mass 6941(2 u) is composed of two stable Isotopes ( and, the latter being the more abundant Helium-4 ( or) is a non- Radioactive and light Isotope of Helium. 7 MeV  )  +  32He  (  2. This article is about the elemental isotope For the record label Helium 3 see Muse or A&E Records. 3 MeV  )
(9)  32He  +  63Li  →  2 42He  +  p+                  +  16. This article is about the elemental isotope For the record label Helium 3 see Muse or A&E Records. Naturally occurring Lithium ( Li) (standard atomic mass 6941(2 u) is composed of two stable Isotopes ( and, the latter being the more abundant Helium-4 ( or) is a non- Radioactive and light Isotope of Helium. The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive 9 MeV
(10)  p+  +  115B  →  3 42He                      +  8. The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive Boron ( B)Standard atomic mass 10811(7 u Table Helium-4 ( or) is a non- Radioactive and light Isotope of Helium. 7 MeV

For reactions with two products, the energy is divided between them in inverse proportion to their masses, as shown. In most reactions with three products, the distribution of energy varies. For reactions that can result in more than one set of products, the branching ratios are given. Some reaction candidates can be eliminated at once. [9]The D-6Li reaction has no advantage compared to p+-115Bbecause it is roughly as difficult to burn but produces substantially more neutrons through 21D-21Dside reactions. The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive Boron ( B)Standard atomic mass 10811(7 u Table Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth There is also a p+-73Lireaction, but the cross section is far too low, except possibly when Ti> 1 MeV, but at such high temperatures an endothermic, direct neutron-producing reaction also becomes very significant. The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive Naturally occurring Lithium ( Li) (standard atomic mass 6941(2 u) is composed of two stable Isotopes ( and, the latter being the more abundant Finally there is also a p+-94Bereaction, which is not only difficult to burn, but 94Becan be easily induced to split into two alpha particles and a neutron. The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive Although Beryllium ( Be) has multiple Isotopes, only one of these isotopes is stable as such it is considered a monoisotopic element Although Beryllium ( Be) has multiple Isotopes, only one of these isotopes is stable as such it is considered a monoisotopic element In addition to the fusion reactions, the following reactions with neutrons are important in order to "breed" tritium in "dry" fusion bombs and some proposed fusion reactors:

n0  +  63Li  →  31T  +  42He
n0  +  73Li  →  31T  +  42He  +  n0

To evaluate the usefulness of these reactions, in addition to the reactants, the products, and the energy released, one needs to know something about the cross section. This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. Naturally occurring Lithium ( Li) (standard atomic mass 6941(2 u) is composed of two stable Isotopes ( and, the latter being the more abundant Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen. Helium-4 ( or) is a non- Radioactive and light Isotope of Helium. This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. Naturally occurring Lithium ( Li) (standard atomic mass 6941(2 u) is composed of two stable Isotopes ( and, the latter being the more abundant Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen. Helium-4 ( or) is a non- Radioactive and light Isotope of Helium. This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. Any given fusion device will have a maximum plasma pressure that it can sustain, and an economical device will always operate near this maximum. Given this pressure, the largest fusion output is obtained when the temperature is chosen so that <σv>/T² is a maximum. This is also the temperature at which the value of the triple product nTτ required for ignition is a minimum, since that required value is inversely proportional to <σv>/T² (see Lawson criterion). The fusion energy gain factor, usually expressed with the symbol Q, is the ratio of Fusion power produced in a Nuclear fusion reactor to the power required In Nuclear fusion research the Lawson criterion, first derived by John D (A plasma is "ignited" if the fusion reactions produce enough power to maintain the temperature without external heating. ) This optimum temperature and the value of <σv>/T² at that temperature is given for a few of these reactions in the following table.

Nucleosynthesis
fuel T [keV] <σv>/T² [m³/s/keV²]
21D-31T 13. Nucleosynthesis is the process of creating new atomic nuclei from preexisting Nucleons (protons and neutrons 6 1. 24×10-24
21D-21D 15 1. 28×10-26
21D-32He 58 2. 24×10-26
p+-63Li 66 1. 46×10-27
p+-115B 123 3. 01×10-27

Note that many of the reactions form chains. For instance, a reactor fueled with 31T and 32He will create some 21D, which is then possible to use in the 21D-32He reaction if the energies are "right". An elegant idea is to combine the reactions (8) and (9). The 32He from reaction (8) can react with 63Li in reaction (9) before completely thermalizing. This produces an energetic proton which in turn undergoes reaction (8) before thermalizing. A detailed analysis shows that this idea will not really work well, but it is a good example of a case where the usual assumption of a Maxwellian plasma is not appropriate. The Maxwell–Boltzmann distribution is a Probability distribution with applications in Physics and Chemistry.

Neutronicity, confinement requirement, and power density

The only fusion reactions thus far produced by humans to achieve ignition are those which have been created in hydrogen bombs; the first of which, Ivy Mike, is shown here.
The only fusion reactions thus far produced by humans to achieve ignition are those which have been created in hydrogen bombs; the first of which, Ivy Mike, is shown here. The fusion energy gain factor, usually expressed with the symbol Q, is the ratio of Fusion power produced in a Nuclear fusion reactor to the power required The Teller–Ulam design is a Nuclear weapon design which is used in Megaton -range Thermonuclear weapons and is more colloquially referred to as "the Ivy Mike was the codename given to the first US test of a fusion device where a major part of the explosive yield came from fusion

Any of the reactions above can in principle be the basis of fusion power production. Fusion power is power generated by Nuclear fusion reactions In this kind of reaction two light atomic nuclei fuse In addition to the temperature and cross section discussed above, we must consider the total energy of the fusion products Efus, the energy of the charged fusion products Ech, and the atomic number Z of the non-hydrogenic reactant.

Specification of the 21D-21D reaction entails some difficulties, though. To begin with, one must average over the two branches (2) and (3). More difficult is to decide how to treat the 31T and 32He products. 31T burns so well in a deuterium plasma that it is almost impossible to extract from the plasma. The 21D-32He reaction is optimized at a much higher temperature, so the burnup at the optimum 21D-21D temperature may be low, so it seems reasonable to assume the 31T but not the 32He gets burned up and adds its energy to the net reaction. Thus we will count the 21D-21D fusion energy as Efus = (4. 03+17. 6+3. 27)/2 = 12. 5 MeV and the energy in charged particles as Ech = (4. 03+3. 5+0. 82)/2 = 4. 2 MeV.

Another unique aspect of the 21D-21D reaction is that there is only one reactant, which must be taken into account when calculating the reaction rate.

With this choice, we tabulate parameters for four of the most important reactions.

fuel Z Efus [MeV] Ech [MeV] neutronicity
21D-31T 1 17. 6 3. 5 0. 80
21D-21D 1 12. 5 4. 2 0. 66
21D-32He 2 18. 3 18. 3 ~0. 05
p+-115B 5 8. 7 8. 7 ~0. 001

The last column is the neutronicity of the reaction, the fraction of the fusion energy released as neutrons. Aneutronic fusion is any form of Fusion power where no more than 1% of the total energy released is carried by Neutrons Since the most-studied fusion reactions This is an important indicator of the magnitude of the problems associated with neutrons like radiation damage, biological shielding, remote handling, and safety. For the first two reactions it is calculated as (Efus-Ech)/Efus. For the last two reactions, where this calculation would give zero, the values quoted are rough estimates based on side reactions that produce neutrons in a plasma in thermal equilibrium.

Of course, the reactants should also be mixed in the optimal proportions. This is the case when each reactant ion plus its associated electrons accounts for half the pressure. Assuming that the total pressure is fixed, this means that density of the non-hydrogenic ion is smaller than that of the hydrogenic ion by a factor 2/(Z+1). Therefore the rate for these reactions is reduced by the same factor, on top of any differences in the values of <σv>/T². On the other hand, because the 21D-21D reaction has only one reactant, the rate is twice as high as if the fuel were divided between two hydrogenic species.

Thus there is a "penalty" of (2/(Z+1)) for non-hydrogenic fuels arising from the fact that they require more electrons, which take up pressure without participating in the fusion reaction. (It is usually a good assumption that the electron temperature will be nearly equal to the ion temperature. Some authors, however discuss the possibility that the electrons could be maintained substantially colder than the ions. In such a case, known as a "hot ion mode", the "penalty" would not apply. ) There is at the same time a "bonus" of a factor 2 for 21D-21D because each ion can react with any of the other ions, not just a fraction of them.

We can now compare these reactions in the following table.

fuel <σv>/T² penalty/bonus reactivity Lawson criterion power density
21D-31T 1. 24×10-24 1 1 1 1
21D-21D 1. 28×10-26 2 48 30 68
21D-32He 2. 24×10-26 2/3 83 16 80
p+-115B 3. 01×10-27 1/3 1240 500 2500

The maximum value of <σv>/T² is taken from a previous table. The "penalty/bonus" factor is that related to a non-hydrogenic reactant or a single-species reaction. The values in the column "reactivity" are found by dividing 1. 24×10-24 by the product of the second and third columns. It indicates the factor by which the other reactions occur more slowly than the 21D-31T reaction under comparable conditions. Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen. The column "Lawson criterion" weights these results with Ech and gives an indication of how much more difficult it is to achieve ignition with these reactions, relative to the difficulty for the 21D-31T reaction. In Nuclear fusion research the Lawson criterion, first derived by John D Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen. The last column is labeled "power density" and weights the practical reactivity with Efus. It indicates how much lower the fusion power density of the other reactions is compared to the 21D-31T reaction and can be considered a measure of the economic potential. Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen.

Bremsstrahlung losses in quasineutral, isotropic plasmas

The ions undergoing fusion in many systems will essentially never occur alone but will be mixed with electrons that in aggregate neutralize the ions' bulk electrical charge and form a plasma. The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J Electric charge is a fundamental conserved property of some Subatomic particles which determines their Electromagnetic interaction. In Physics and Chemistry, plasma is an Ionized Gas, in which a certain proportion of Electrons are free rather than being bound The electrons will generally have a temperature comparable to or greater than that of the ions, so they will collide with the ions and emit x-ray radiation of 10-30 keV energy (Bremsstrahlung). X-radiation (composed of X-rays) is a form of Electromagnetic radiation. Bremsstrahlung ( pronounced, from German de ''bremsen'' "to brake" and de ''Strahlung'' "radiation" i The Sun and stars are opaque to x-rays, but essentially any terrestrial fusion reactor will be optically thin for x-rays of this energy range. Opacity is the measure of impenetrability to electromagnetic or other kinds of radiation especially visible Light. Optical depth is a measure of transparency, and is defined as the negative Logarithm of the fraction of Radiation (or Light) that is scattered X-rays are difficult to reflect but they are effectively absorbed (and converted into heat) in less than mm thickness of stainless steel (which is part of a reactor's shield). The ratio of fusion power produced to x-ray radiation lost to walls is an important figure of merit. This ratio is generally maximized at a much higher temperature than that which maximizes the power density (see the previous subsection). The following table shows the rough optimum temperature and the power ratio at that temperature for several reactions. [10]

fuel Ti (keV) Pfusion/PBremsstrahlung
21D-31T 50 140
21D-21D 500 2. 9
21D-32He 100 5. 3
32He-32He 1000 0. 72
p+-63Li 800 0. 21
p+-115B 300 0. 57

The actual ratios of fusion to Bremsstrahlung power will likely be significantly lower for several reasons. For one, the calculation assumes that the energy of the fusion products is transmitted completely to the fuel ions, which then lose energy to the electrons by collisions, which in turn lose energy by Bremsstrahlung. However because the fusion products move much faster than the fuel ions, they will give up a significant fraction of their energy directly to the electrons. Secondly, the plasma is assumed to be composed purely of fuel ions. In practice, there will be a significant proportion of impurity ions, which will lower the ratio. In particular, the fusion products themselves must remain in the plasma until they have given up their energy, and will remain some time after that in any proposed confinement scheme. Finally, all channels of energy loss other than Bremsstrahlung have been neglected. The last two factors are related. On theoretical and experimental grounds, particle and energy confinement seem to be closely related. In a confinement scheme that does a good job of retaining energy, fusion products will build up. If the fusion products are efficiently ejected, then energy confinement will be poor, too.

The temperatures maximizing the fusion power compared to the Bremsstrahlung are in every case higher than the temperature that maximizes the power density and minimizes the required value of the fusion triple product. In Nuclear fusion research the Lawson criterion, first derived by John D This will not change the optimum operating point for 21D-31T very much because the Bremsstrahlung fraction is low, but it will push the other fuels into regimes where the power density relative to 21D-31T is even lower and the required confinement even more difficult to achieve. Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen. Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth Tritium (ˈtɹɪtiəm symbol or, also known as Hydrogen-3) is a radioactive Isotope of Hydrogen. For 21D-21D and 21D-32He, Bremsstrahlung losses will be a serious, possibly prohibitive problem. Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth Deuterium, also called heavy hydrogen, is a Stable isotope of Hydrogen with a Natural abundance in the Oceans of Earth This article is about the elemental isotope For the record label Helium 3 see Muse or A&E Records. For 32He-32He, p+-63Li and p+-115B the Bremsstrahlung losses appear to make a fusion reactor using these fuels with a quasineutral, anisotropic plasma impossible. This article is about the elemental isotope For the record label Helium 3 see Muse or A&E Records. This article is about the elemental isotope For the record label Helium 3 see Muse or A&E Records. The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive Naturally occurring Lithium ( Li) (standard atomic mass 6941(2 u) is composed of two stable Isotopes ( and, the latter being the more abundant The proton ( Greek πρῶτον / proton "first" is a Subatomic particle with an Electric charge of one positive Boron ( B)Standard atomic mass 10811(7 u Table Some ways out of this dilemma are considered—and rejected—in Fundamental limitations on plasma fusion systems not in thermodynamic equilibrium by Todd Rider. [11] This limitation does not apply to non-neutral and anisotropic plasmas; however, these have their own challenges to contend with.

See also

References

  1. ^ The Most Tightly Bound Nuclei
  2. ^ Access : Desktop fusion is back on the table : Nature News
  3. ^ http://www.nature.com/nature/journal/v434/n7037/extref/nature03575-s1.pdf
  4. ^ UCLA Crystal Fusion
  5. ^ Physics News Update 729
  6. ^ Coming in out of the cold: nuclear fusion, for real | csmonitor.com
  7. ^ Nuclear fusion on the desktop ... really! - Science - MSNBC.com
  8. ^ FusEdWeb | Fusion Education
  9. ^ http://theses.mit.edu/Dienst/UI/2.0/Page/0018.mit.theses/1995-130/30?npages=306
  10. ^ http://theses.mit.edu/Dienst/UI/2.0/Page/0018.mit.theses/1995-130/26?npages=306
  11. ^ http://fusion.ps.uci.edu/artan/Posters/aps_poster_2.pdf Portable Document Format (PDF)

External links

Dictionary

nuclear fusion

-noun

  1. (physics) The combining of the nuclei of small atoms to form the nuclei of larger ones, with a resulting release of large quantities of energy; the process that makes the sun shine, and hydrogen bomb explode.
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