What is Fusion: Definition and 843 Discussions

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). The difference in mass between the reactants and products is manifested as either the release or the absorption of energy. This difference in mass arises due to the difference in atomic binding energy between the nuclei before and after the reaction. 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 process that produces nuclei lighter than iron-56 or nickel-62 will generally release energy. These elements have relatively small mass per nucleon and large binding energy per nucleon. Fusion of nuclei lighter than these releases energy (an exothermic process), while fusion of heavier nuclei results in energy retained by the product nucleons, and the resulting reaction is endothermic. The opposite is true for the reverse process, nuclear fission. 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 extreme astrophysical event of a supernova can produce enough energy to fuse nuclei into elements heavier than iron.
In 1920, Arthur Eddington suggested hydrogen-helium fusion could be the primary source of stellar energy. Quantum tunneling was discovered by Friedrich Hund in 1929, and shortly afterwards Robert Atkinson and Fritz Houtermans used the measured masses of light elements to show that large amounts of energy could be released by fusing small nuclei. Building on the early experiments in artificial nuclear transmutation by Patrick Blackett, laboratory fusion of hydrogen isotopes was accomplished by Mark Oliphant in 1932. In the remainder of that decade, the theory of the main cycle of nuclear fusion in stars was worked out by Hans Bethe. Research into fusion for military purposes began in the early 1940s as part of the Manhattan Project. Self-sustaining nuclear fusion was first carried out on 1 November 1952, in the Ivy Mike hydrogen (thermonuclear) bomb test.
Research into developing controlled fusion inside fusion reactors has been ongoing since the 1940s, but the technology is still in its development phase.

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  1. S

    A Muonic hydrogen dissociation energy and cross-section

    Is the dissociation energy of a muonic molecular hydrogen ion the same as an ordinary molecular hydrogen ion? Would the cross-section for dissociation be the same as an ordinary molecular hydrogen ion? I am trying to determine the fusion rate for muon-catalyzed fusion in warm dense plasma, and I...
  2. D

    B Energy production that converts Hydrogen to Iron?

    Suppose a craft derived its energy from fusion— converting Hydrogen into Iron… If it started with a kilo of Hydrogen, how much mass of Iron would it have at the end and how much energy would be extracted?
  3. Mathiasrd

    Need help ordering parts for a nuclear fusion reactor

    Sorry for bad english, does anyone know where I can purchase a spherical vacuum chamber made from metal, that preferably ships internationally ?
  4. R

    Why can't we simply use an atomic bomb to get the fusion working?

    why can not simply explode an atomic bomb inside a recint with plasma and hydrogen so the temperature and power generated will make the fusion working
  5. billtodd

    Metal, Rock, Instrumental Rock and Fusion

    A classical from the previous century in Fusion: A prog Chord Change And a little bit Metal: Share your own from those genres.
  6. H

    Music Today's Fusion Music: T Square, Cassiopeia, Rei & Kanade Sato

    The musical style called fusion lasted only a few years in the West but caught on in Japan. I supposed that's natural for a nation whose symbol is a fusion-fueled fireball. The exponents were T Square and Cassiopeia, which are getting pretty old but still doing it. Their influence was mostly...
  7. Deric Xavier

    B Detection of transuranic elements in astronomical events

    Is it possible to detect transuranic elements that may eventually occur during big astronomical events? I know that transuranic elements are radioactive, so we could maybe measure the radiation that is being emited, but how could we separate the radiation that comes from the transuranic elements...
  8. S

    I Thoughts on this article: The Universe Is More in Our Hands Than Ever Before

  9. benswitala

    I Can Neutron-X Fusion Reactions Overcome the Repulsion Problem in Fusion Energy?

    Hi, I was reading about fusion reactions recently, and it was pointed out that the problem seems to be that positively charged nuclei repel each other. If that is the problem, why don't scientists try to go with another fusion reaction? Would it be possible to have fusion if neutrons fuse...
  10. J

    B Fusion, bigger output than input?

    Fusion has bigger output then input, because produce more energy than to initiate reaction. This is allways case, for example 100kg of wood burning produce much more energy then initiate fire with one match fire. Can someone explain this statement?
  11. S

    Big announcement about fusion energy coming soon (Dec-2022)

  12. M

    Cylindrical and Symmetrical Nuclear Fusion Reactor

    Hello ! I would like to consult you about this cylindrical nuclear reactor model that I have been thinking of with the idea of reducing the friction of the plasmas with the walls of the Toroidal nuclear fusion reactors that causes the plasma temperature to drop and the nuclear reactions to stop...
  13. thewowsignal

    Nuclear fusion and anti-nuclear technology

    I want to start a serious discussion here about our future on this small planet. This thread is especially dedicated to those of you, who are enthusiastic about atomic energy and energy crisis.
  14. A

    Fusion tritium problem solution?

    There are many articles like this one https://www.science.org/content/article/fusion-power-may-run-fuel-even-gets-started Where scientists talk about the problem of obtaining tritium even if the fusion engineering itself finally crosses the "net gain" margin for electricity production. Here is...
  15. A

    B Deuterium combustion within inertial fusion schemes

    Hydrogen as well as Deuterium are both flammable chemically, I read that both hydrogen as well as deuterium can ignite/combust upon compression even in ordinary ICE engines. Hydrogen has been investigated and used as fuel for internal combustion engines. Now in a inertial fusion approach the...
  16. kyphysics

    Nuclear Fusion Breakthrough....What Does This Mean?

    Nuclear Fusion Breakthrough Confirmed: California Team Achieved Ignition BY JESS THOMSON ON 8/12/22 AT 9:20 AM EDT https://www.newsweek.com/nuclear-fusion-energy-milestone-ignition-confirmed-california-1733238 For those of us not literate in the field, how significant is this and what are the...
  17. Strato Incendus

    Writing: Input Wanted A dangerous space mission that requires a lot of helping hands

    As I've mentioned in a few previous threads, at the midpoint of my sci-fi story on a generation ship, I need a disaster that wipes out about a third of the (male half of) the crew. Several people have suggested things like "a virus that disproportionately affects men", but that didn't quite cut...
  18. D

    Nuclear fusion energy calculations

    Me again! For a sci-fi story I'm working on, I've created a sci-fi technology called an Aneutronic Triple Alpha Fusion Reactor. It works via aneutronic fusion, in this case, fusing Deuterium with Helium 3, but it also mimics the triple alpha process found within stars to maximise fuel use...
  19. Melbourne Guy

    Proton-Boron fusion feasibility

    A PF search results in some discussion of proton-boron fusion, and from those posts, it seems that cross-section issues limit the likelihood of this type of fusion device. Now, Avalanche Energy (https://www.avalanche.energy/index.html) is claiming a design that is backpack sized and capable of...
  20. Leo Liu

    How does D-T fusion reaction utilize its waste to create more fuel?

    In Britannica's article on nuclear fusion, I came across the following description of the recycle of triton and neutrons: What puzzle me are why the tritons are produced from the D-T fusion reaction, given that the products are alpha particle, neutron, and energy; and how the neutrons can be...
  21. A

    Inertial confinement fusion (First light, NIF, etc)

    More or less all ICF schemes seem to be similar to the first artificial fusion method (also inertial) of the secondary of the hydrogen bomb. Before I present the question let me show just another ICF approach recently done. The company is called "first light fusion", Their method is essentially...
  22. M

    What kind of fusion do you think Star Wars has?

    Fusion power is mentioned a lot in Star Wars. In the Bad Batch arc of the second to last season of Clone Wars, the Separatist facility was powered by a fusion reactor. The A-wing is powered by fusion. GNK droids are walking fusion batteries and they have made fusion furnaces the size of a small...
  23. A

    Music Fusion of Western musical instruments

    Western musical instruments Western musical instruments images Trumpet and Saxophone. Is it possible to design and construct western musical instruments as a fusion of two or more functions and features? I mean to say Guitar, Violin, Trumpet, Saxophone, Piano etc integrated into a single...
  24. TechmoUnity

    B Assistance finding the nuclear energy difference during nuclear fusion

    Hello! I have finished high school quite a few years ago. I did a physics course that went over nuclear fusion and fission, and I quite enjoyed it. However, I unfortunately no longer have those textbooks (I sold them on as many people do). Now I am doing a bit of programming in the field of...
  25. Andy Meadowcroft

    B Andy Meadowcroft - Introduction (and a question about nuclear fusion)

    How did you find PF?: I searched google for a Physics Forum I searches Google for a Physics Forum, to enable me to pose a question to people who know more about physics than I do. I have no detailed physics knowledge, but do read a lot of science articles, so understand most of the basics. A...
  26. G

    Job Skills Recent BS in Comp Sci graduate looking to get into fusion

    Hi all, per the title I'm looking for career advice on getting into fusion. Whether that is working at a fusion company or doing research in the field. The university I graduated from was the best I could get into at the time, due to the poor grades I left there with (~2.5 GPA) from 06-08. I...
  27. C

    Fusion catalized from graphite?

    My name "crystal catalyst" because I believe that is the best way to achieve fusion. It was inspired by the Pons and Fleishman experiments. Were they actually right? I don't know. But maybe they were on the right track, as having the fusion fuel loaded inside a crystal catalyst that holds the...
  28. BWV

    Halite / Centurion and fission - fusion power plants

    Its unclear to me what exactly these tests entailed and how much today is still top secret. They involved inertial confinement fusion with x-rays from a fission explosion. never see this discussed - forgetting about political issues with fission, how feasible is a fusion reactor utilizing...
  29. j2mhall

    B Fusing Neutrons: Can It Lead to Cold Fusion?

    Hi Is it possible to get two neutrons to fuse together to form helium? If so, would it not make cold fusion possible?
  30. BWV

    B Exploring Extra-Stellar Fusion: Real Science

    Sorry for the clickbaity title, real science question- The part below of the Wikipedia article on Nuclear Fusion seems to imply that some miniscule number of fusion reactions might occur randomly at normal temperatures (of course no ability to turn this into an energy source) So just due to...
  31. A

    Sound waves inside an inert gas fusion reactor

    Hey, its that under educated guy again, I hope the mighty big brains can spare me my feelings. Anyways, I saw this toy that levitated a ball of water using nothing but sound waves. So naturally I tried to apply this to a plasma and fusion. Using a inert gas reactor, or a fusor for that matter or...
  32. neilparker62

    I NIF Reaches Threshold of Fusion Ignition

    Is this a 'big deal' ? https://www.llnl.gov/news/national-ignition-facility-experiment-puts-researchers-threshold-fusion-ignition
  33. phyzguy

    Major Nuclear Fusion Milestone: Ignition Achieved

    https://phys.org/news/2021-08-major-nuclear-fusion-milestone-ignition.html Anybody know any more? Like what they did differently from earlier trials.
  34. M

    How to compute how much energy is released in nuclear fusion?

    I thought the first step is to compute the loss of mass. ##\Delta m=m(_1^2\textrm{H})+m(_1^3\textrm{H})-m(_2^4\textrm{He})-m(_0^1\textrm{n})=2.0141018u+3.0160493u- 4.0026033u-1.0086650u=0.0188828u##. The corresponding reaction energy is ##0.0188828 \cdot 931,5MeV=17.54MeV\approx 2.81\cdot...
  35. P

    Exploring the Possibility of Proton-K Potassium Fusion and the Forces Involved

    Hi everyone! I was wondering if it is possible for a proton (H+) to fuse with an atom of potassium (K39 or K41) to create (Ca40+ or Ca42+)? And if so what types of forces would need to be overcome to make this possible? Thanks in advance for any help and sorry if this is a stupid question!:sorry:
  36. Xilus

    Have you heard about the French Fusion Reactor?

    Homework Statement:: French Fusion Reactor Relevant Equations:: F=ma Hey anyone here working on the French Fusion reactor? Heard about it over the radio. ITER just been reading the annual reports from CERN. Kind of a fun read if you haven’t read it yet.
  37. A

    Fusion reactors are neutron sources AKA fission bomb factories?

    Assumptions: 1) Fusion reactors are easily obtainable. Every spacecraft or hover-car has one. 2) Fusion reactors are neutron sources. 3) Neutron sources are the "difficult bit" in the enrichment of uranium and plutonium. 4) Uranium and plutonium are "freely" available in asteroids or...
  38. M

    Specific latent heat of fusion of ice question

    a) Ew = EL + Ei mwc(T2-T1) = miL + mic(T2-0) 160 x 4.2 x (30 - 20) = 20L + (20 x 4.2 x 20) L = (6720 - 1680)/20 = 252 J/g b) accounting for 3 gram of melted ice 160 x 4.2 x (30 - 20) = (20 - 3) + (20 x 4.2 x 20)...
  39. L

    B Nuclear fusion question -- Calculations for Hydrogen fusing into Helium

    I read in 2 books that 4 atoms of Hydrogen fuse and give 1 atom of Helium and 2 electrons, and these 2 electrons convert to light. And that the mass of the Helium is less than the mass of the 4 atoms of Hydrogen, thus that the mass lost converted to light too. But I sum up the masses of...
  40. A

    Would He3 make fusion easier? :- Can a fusion rocket launch from Moon?

    Heard talk about He3 on the Moon and launching a fusion rocket. Is this all just a mashup of Sci-fi ideas?
  41. hyperiontorus

    Levels of Civilization Based on Deuterium

    Summary:: Similar to the Kardashev Scale, create a means for forming a hierarchy of civilization based on deuterium access. I'm interested in the fusion process using deuterium, and I've noted that it remains (to this day) the greatest source of energy of any reactions. Because of this reason...
  42. W

    A How do heavier nuclei maintain stability despite requiring energy for fusion?

    I understand overall decrease in potential energy of Lighter nuclei releases energy on Fusion- but for heavier nuclei - energy is required- means overall potential energy is not decreased - than how these heavier nuclei sustained their stability.
  43. Meaning

    [Fusion] Basic concept behind the Stellarator

    Hey I am starting a course on plasma physics, I don't understand the principle of Stellarators. If there is no plasma current, how is the mhd equilibrium achieved (J \times B = grad P)? I apologize if the answer is obvious, but I starting with this
  44. gleem

    A New Thruster Based on Fusion

    Princeton University researchers have https://www.pppl.gov/news/2021/01/new-concept-rocket-thruster-exploits-mechanism-behind-solar-flares a new type of rocket thruster using a fusion reactor which is used to produce plasmoid bubbles. These bubbles are extracted from the reactor at speed of 20...
  45. T

    B Where do the electrons go? (in stellar nuclear fusion)

    I have to give a presentation about natural Radiation and I am very happy about it because it includes Astrophysics. I want to explain to my audience how the stars produce cosmic rays. I thought about explaining to them how nuclear fusion and that kind of stuff works but then I realized that I...
  46. A

    Limiting Factors for Liner Implosion in Z Machine Fusion

    What is the limiting factor for a liner and it's implosion in a Z type machine? I wonder have they tried or is it possible to use liners that have a larger radius and contain more gas or gas under higher pressure aka more dense? Are the dimensions of the liner so small because having a larger...
  47. smaharoof

    Programs Fusion Energy Research Pathway

    Hello all, I have a community college student who is deciding on his major. He is really interested in Fusion energy and wants to pursue that path. He was in the Engineering Program and now, after doing some research, believes he should be in the physics program (A.S. degree in Physics). The...
  48. B

    Hydrogen Fusion Engine: Steel Sphere & Sulfuric Acid

    Have a thick steel hollow sphere with a inside radius of 20 cm. Then fill it up with sulfuric acid and add water. Then remove the oxygen ions. then give the sphere a negative charge and all the hydrogen ions move to the surface of the inside sphere. then charge sphere positive and the hydrogen...
  49. J

    I Is Nuclear fusion possible at room temperature with high preassure?

    If it is theoretically possible to compress hydrogen to core of the sun pressures at normal room temperature (practically impossible), the molecules become so close to each other that they could fuse at room temperature without the need of creating millions of degrees kelvin.