Questions tagged [fusion]
The fusion tag is used for questions about nuclear fusion, both the basic process at a physical level and it's use as a potential energy source.
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Does fusion only occur with ions?
In nuclear fusion, the particles require enough energy to overcome the Coulomb barrier. The Coulomb barrier is caused by the Coulomb force, which is created by the protons repelling each other because ...
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24 views
Calculation of number of nuclear fusion reaction per cubic meter or kilo
In wikipedia article about Nuclear fusion there is a list of nuclear fusion reaction here.
Is there a equation how to calculate number of nuclear fusion reaction per second per cubic meter or per kg ...
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1answer
18 views
How would I go about calculating the energy input needed for a cyclotron reactor?
I'm trying to do some math regarding cyclotron reactors. I've figured out how to calculate the radius of a particle's motion in the cyclotron, a rough way to calculate energy output, but I have looked ...
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1answer
23 views
Is a chain fusion reaction of deuterium oxide (heavy water).possible?
I think it is the case that at very high temperatures that two deuterium atoms can be made to fuse to produce helium and a release of energy. I think under appropriate physical conditions this can ...
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2answers
88 views
How are thermonuclear weapons possible?
Given the fact that thermonuclear devices are a mix of fission through enriched uranium whose energy initiates the fusion in surrounding deuterium. Question is (how come) fission raises temperature so ...
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3answers
62 views
Energy from fusion beyond iron peak
In the diagram of nuclear binding energy per nucleon Eb/A (vertical axis) and mass number A (horizontal axis), Fe-56 has one of the highest values. Many authors state that nuclear fusion can only ...
4
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3answers
159 views
Is gravity a factor for sustaining fusion?
Does gravity affect a Fusion reactors ability to sustain a reaction? If so has there been any experiments done or planed for in space?
Holding / maintaining shape might be a lot easier with less ...
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1answer
34 views
Any way to definitively determine the products of deuterium-deuterium fusion?
I was doing some reading and came across these two reactions:
$D + D \rightarrow \:^3He + n + 3.27 MeV$
and:
$D + D \rightarrow \:^3H + H + 4.03 MeV$
(from here: http://hyperphysics.phy-astr.gsu....
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1answer
45 views
How is the energy output released in a proton-proton fusion reaction?
$$\rm p + p \to {}^2H + e^+ + v_e$$
The net energy output for this reaction, not including the electron-positron annihilation that likely would occur, is 0.423 MeV - according to my math and sources ...
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0answers
24 views
Is there a mathematical model for predicting when gamma rays are produced in radioactive decay?
My understanding of gamma ray emission from radioactivity is that the daughter particle is in an excited state, which then produces a gamma ray as the electron drops energy levels. In the case of ...
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2answers
67 views
Could you use the detonation of a Hydrogen bomb or atomic bomb to start a nuclear fusion reactor [closed]
Would this lead to a reactor that produced more energy than you put in?
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3answers
121 views
Is high temperature **required** for nuclear fusion?
Tl;dr: Can fusion be achieved only by speeding up particles to high enough speeds to smash into each other?
I know that it is necessary for protons, or any oppositely-charged particles for that ...
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1answer
78 views
How does the $p+p + e^-\rightarrow D + \gamma\gamma+ \nu$ reaction proceed in the sun?
In this video on nuclear fusion the explanation of the reaction $p+p\rightarrow D + \nu + \gamma\gamma$ is that the two protons collide, form a weakly bound state, and then sometimes decay into the ...
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28 views
How To Simulate Muon Induced Nuclear Fusion?
I am familiar with euler-lagrange equations which can be used to simulate a mechanical system, something like an inverted pendulum on a cart. How can I simulate a volume of deuterium and tritium with ...
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1answer
39 views
Is relativistic channeled electron catalyzed fusion possible?
A few words first about muon catalyzed fusion.
You can see this question sigoldberg1 answer, and this link.
"The muon may bump the electron from one of the hydrogen isotopes. The muon, 207 ...
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1answer
33 views
NAS report on fast ignition
I'm looking for a paper, or much more likely a small part of a large report, by the National Academy of Sciences from around 2013 on the topic of fusion. The report mentions the fast ignition approach ...
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1answer
65 views
Has proton-proton fusion ever been seriously considered for an artificial fusion reactor?
All contemporary efforts to perform nuclear fusion as a source of power have focused on reactions between isotopes (often deuterium, tritium, or He3) and/or light elements (often boron or lithium ...
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1answer
74 views
Ultra Cold Neutrons in a Bottle Question
If you take a large amount of ultracold neutrons and confine them in a bottle would they then decay into protons and then fuse because they are so tightly condensed that the protons, once neutrons, ...
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79 views
How do we recover fusion energy from gamma photons
Most fusion reactions create energy in form of hard gamma radiations. A single gamma photon carries energy orders of magnitude higher than any ionization level. Even if we develop some hardcore ...
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1answer
24 views
Tuning Drifts in Tokamaks
If we managed to make over 50 % of the drifting of the guiding centers of the gyrating particles inside a tokamak to occur into the inwards direction, away from the tokamak walls, would that allow us ...
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0answers
40 views
Intermediate product of CNO cycle
CNO cycle of stellar nucleosynthesis involves several steps in which different isotopes of Carbon, Nitrogen, and Oxygen are transmuted into each other when hit by a ...
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1answer
26 views
Why doesn't a deuterium-deuterium reaction usually yield Helium-4?
I assume the above reaction is less energetically favorable than the creation of He-3 (plus a neutron) or tritium plus a proton? But why/how?
Or are the hard, hot, fast collisions too much for it to ...
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1answer
89 views
Why does fusion above nickel 56 require energy?
I've always struggled with the concept of fission and fusion. I mean I can show a mass deficit with math easily enough but I have always struggled understanding the fundamental concept of why things ...
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6answers
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Is fission/fusion to iron the most efficient way to convert mass to energy?
Is fission/fusion of any element to iron-56 (or nickel-62?) the best way to convert mass to energy, that doesn't involve black holes?
In other words, will we be always limited to convert only about 1%...
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1answer
51 views
Is there a “pinch effect” in a Tokamak?
Is there a "pinch effect" in a Tokamak, like in a linear Z-pinch or in a circular pinch (the ZETA machine from the late 50's)? Tokamaks run in a pulsed mode and a powerful circular current is induced ...
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50 views
How can corium eating its way into water tanks cause a megaton scale explosion? [duplicate]
The 2019 miniseries "Chernobyl" appears to state that the "lava like" substance of melted radioactive matter from the core, the so-called "corium", could eat its way down into the water reservoirs ...
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2answers
103 views
How can Sun burn in space?
If there is no oxygen in space how can sun burn in space. (even though I know fire is caused by nuclear reaction inside sun)
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1answer
63 views
What if a fusion reactor had moving parts?
I have never dug into fusion physics, but from what I gather one of the main problems is confining the fusion in a small region of space for long enough to get enough helium fused to counterbalance ...
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3answers
390 views
Whats the next step after commercial fusion reactors? [closed]
I'm trying to write some science fiction where they've had nuclear fusion working for quite sometime, interplanetary travel is no problem, and they're debating making the next step to a radical new, ...
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0answers
36 views
Released energy during fusion reaction
Click to view the video at required time
According to the video in the link above
the binding energy for deuterium is about 2 MeV and the binding energy for tritium is about 8 MeV so the total for ...
2
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0answers
63 views
Why is the D+P fusion reaction not considered for large-scale power production?
I know that D+D (fusion of deuterium + deuterium nuclei) as well as D+T (fusion of deuterium and tritium nuclei) are the reactions most commonly considered for large-scale power production. Why not D+...
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3answers
67 views
Binding energy, fission and fusion
My high school physics book doesn't elaborate the idea of binding energy and how it's related to fission and fusion adequately in a way that made me have wrong thoughts about these ideas.
What i ...
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2answers
112 views
Explain to me why the following reaction can happen in big stars but not on earth
$$
\rm
{}^{12}C +{}^{12}C\rightarrow {}^{20}Ne + {}^4He
$$
why doesn't this reaction occur on earth? but occurs in big stars?
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1answer
21 views
How can you determine how much neutron shielding is necessary for a given neutron source?
Trying to make a fusor at home and I was wondering if there is an industry standard or perhaps an equation to determine how and what type of neutron shielding is necessary to protect against the high ...
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0answers
27 views
CNO-cycle in Population III stars [duplicate]
It has been stated several times here and probably elsewhere that the first population III stars were unable to undergo H-to-He fusion via the CNO cycle as there was virtually no carbon-12 at the ...
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1answer
58 views
What is the maximum energy that can be released by thermonuclear device?
Forgive me by posing this somewhat scary question, but it's just out of curiosity I'm asking it.
In this video we're witnessing the beautiful and at the same time horrific blast of the tsar bomba, ...
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9 views
What is Incoming wave boundary condition (IWBC) in context of nuclear fusion reaction?
For calculation of fusion cross section at sub barrier energies, instead of regular boundary condition we impose Incoming wave boundary condition (IWBC). How does this different from normal boundary ...
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43 views
Sensitivity of latent heat of fusion of ice on temperature and pressure
The enthalpy of fusion is the heat necessary to convert 1 kg of ice to liquid water. According to Wikipedia, this heat equals 333,55 kJ/kg.
Does this heat change with the temperature or pressure and ...
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1answer
49 views
Fusion Kinetic Energy
In fusion, the mass of the reactants is greater than the mass of the products. Thus, mass is lost in fusion. My thinking was that this mass defect is converted into binding energy that is then used to ...
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1answer
48 views
If all we need to do is bombard with alpha particles then why can't we do nuclear fusion like that in the star?
In Chadwick's experiment, alpha particle from a source are bombarded on beryllium atom and fusion occurs to produce carbon atoms. My question is that if it is that easy to cause nuclear fusion, then ...
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4answers
204 views
Does the weak force have an attractive/repulsive force observable in everyday life like the other forces?
After the correct comments, this question is not here to compare gravity's and EM's long range forces' energetics and amplitudes to microscopic scattering amplitudes of such forces as weak and strong. ...
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1answer
60 views
If binding energy (from mass defect) is essentially the strong nuclear force maintaining the nucleus, why is it released?
I am aware that during nuclear fusion for light elements and nuclear fission for heavy elements, the resultant elements have less mass than the original reacting elements (ie the mass defect) because ...
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105 views
Why did the Lockheed Martin compact fusion reactor failed? [duplicate]
What made the compact fusion reactor to not be compact. What assumptions did lokheed made in its simulation that showed that it could work. Can we do anything that could make it work or it is ...
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2answers
41 views
Nuclear Feedback Loop (Fusion and Fission)
What are the main factors that prevent a feedback loop being created by using a hybrid method of fission and fusion. Fusion building up to fissionable materials, and fission breaking down till fusion ...
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1answer
33 views
Is quantitative knowledge of the Standard Model useful in the development of controlled fusion?
I have read articles about quantitative knowledge of particle physics, such as energies, cross sections and particle lifetimes, gained from work at the LHC and other accelerators. Is such quantitative ...
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1answer
57 views
Why the National Ignition Facility try to use 192 laser beams to trigger ignition without heat capsule?
In the discussion of the question "Nuclear Fusion with extremely high pressure and low temperature", the conclusion is only ultrahigh pressure cannot trigger fusion.
But why does NIF try to use 192 ...
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1answer
60 views
What exactly sets the scale in Fusion power plants?
In fusion power plants, larger devices are said to achieve fusion more easily, next step tokamaks like DEMO are even larger than ITER. In a quantitative way, what exactly isn't scale invariant in a ...
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1answer
66 views
is possible to create a nuclear fusion using simple electric arc discharge?
If we have a simple discharge tube filled by deuterium gas or even heavy water, and put tungsten electrodes close to each other to create a huge electric field, then using a megavolt generator to ...
3
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1answer
138 views
Where is nuclear fusion occuring in the Sun?
My understanding is that the sun is basically a sphere of hydrogen with a helium core, and that the hydrogen is undergoing nuclear fusion to produce helium.
There are many images and cross-sectional ...
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105 views
Discussion about a new nuclear fusion design [duplicate]
this company is running a similar project described below.
https://firstlightfusion.com/technology/#our-approach
Let me clarify here, this is not cold fusion. D&T gas will be compressed very ...
