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Questions tagged [fusion]

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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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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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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 ...
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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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Fusion power is dependent on lithium resources? [closed]

I am reading about fusion power and I wonder if in the future countries who use fusion power for electricity will be depended on lithium resources for tritium production or might be able to produce ...
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Discussion about a new nuclear fusion design [duplicate]

Let me clarify here, this is not cold fusion. D&T gas will be compressed very rapidly and its temperature will increase very fast. So, I don't think this is a duplicate question. I have a new ...
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31 views

Magnetic cage for keeping plasma around itself

Let's assume that we have an object in vacuum, venting hydrogen plasma around itself. This object has a powerful internal electrical source, connected to a cage of superconducting wire around it, in ...
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1answer
31 views

Sun's energy and grand unification

According to Wikipedia, The approximate grand unification energy value is equal to $1×10^{25}$ eV or $10^{16}$ GeV This is equal to $1602176$ J. Now, The Earth receives 174 petawatts (PW) ...
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Fusion confusion: what did 12 year old Jackson Oswalt do?

This kid has been showing up in news feeds, but only credulous pop media articles, not hard science reporting. What did he build, and what physics does his device do?
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Proton-Proton, CNO, or white dwarf matter fusion reactor: Is it vaguely possible?

I understand that all efforts at present to make fusion work as an energy source have used light nuclei other than protons due to the fact that the cross section of the proton-proton reaction is just ...
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1answer
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Energy budget of of proton-proton fusion (p-p chain)

How much energy is released in the first nuclear reaction of the p-p chain which produces energy in lower-mass stars like the Sun? The value of 1.44 MeV is given in many sources, but I don't ...
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By how much are various dibaryon states unbound?

It has been known for a long time that the deuteron is stable but the dineutron (nn) and diproton (pp) are not. Many textbooks comment on this, but all the ones I found so far do not give quantitative ...
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How many times do solar protons repeatedly fuse and fission before they form deuteron

In the proton-proton chain reaction in the Sun, the first step is $$p + p \rightarrow \; ^2_2{\rm He} .$$ After this, the most likely thing to happen next is that the reverse reaction occurs: the $^...
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Can we overcome or mitigate the electrostatic force?

After reading this answer and reading a bit more about fusion, I wondered, is there a way to mitigate the electrostatic force between two nuclei so fusion could take place at lower energies? For ...
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1answer
56 views

Is it 'easier' to fuse heavier elements than light ones?

After reading this answer, I wondered the title question. It seems part of our difficulty in harnessing fusion power is controlling the hydrogen and helium (plasma?) while fusion is taking place, i.e. ...
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Why do fusion and fission both release energy?

I only have high school physics knowledge, but here is my understanding: Fusion: 2 atoms come together to form a new atom. This process releases the energy keeping them apart, and is very energetic. ...
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Do only 'giant stars' fuse large amounts of elements other than hydrogen and helium?

Do only giant stars initiate 'full-on' carbon (and higher element) fusion, even though red giants on the larger end of the spectrum create carbon and oxygen via producing helium per the CNO cycle?
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Electronically controlled fusion reactor

It seems that currently, only two types of fusion reactor styles are being used for large scale testing: the Stellarator and the Tokamak. Both of these and a whole bunch of other designs have been ...
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Gamma Photons vs. Muons; Which is more expensive [closed]

Which one takes more energy to produce? I ask as I theorize that keeping the plasma in a fusion reactor is very expensive. Muons, while useful, are too short lived. Maybe... Keeping the plasma at ...
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How do electrons rearrange themselves after a fusion reaction?

The hydrogen atoms can fused inside Sun core into helium without considering about the free electrons, however what about special* cases where two neutrally charged hydrogen atoms collide and fused ...
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1answer
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Forming a Neutron Star: inverse $\beta^-$ decay or electron capture?

There are three different kinds of beta decays: $\beta^-$: n $\rightarrow$ p + e$^-$ + $\overline{\nu}_{e^-}$ $\beta^+$: p $\rightarrow$ n + e$^+$ + $\nu_{e}$ electron capture: p + e$^-$ $\rightarrow$...
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Question about China's Artificial Sun

I have read recently in many websites dedicated to science that China has made an artificial sun hotter than the 'sun'. My question is how did they make a thing that can withstand such a high ...
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2answers
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Lead catalyzed fusion

Consider the following setup: A beam of deuterons is accelerated towards a lead target. With sufficient acceleration (in the MeV range, nothing fancy...), I would expect some of the deuterons to fuse ...
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How could someone calculate the coulomb barrier transparency in 3 dimensions [duplicate]

Transparency is also called probability of transmission, or probability of quantum tunneling.
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What is the probability of fusion reaction happening with energy less than the coulomb barrier (probability of reacting nuclei quantum tunneling)?

$ E_{out} = 4 \pi n_1 n_2 (m_0-m_a) c^2{(\frac {m}{2k_B T})}^{3/2} \int_0^ \infty \sigma(v) v^2 e^{\frac {-mv^2}{2k_B T}} dv$ $m_0$ is the sum masses of the reacting nuclei, $m_a$ is the sum masses ...
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How does Sun's fusion output compare to its gravity?

How does the total solar energy output compare to the total energy required to keep it contained (i.e. Sun's total gravity). In other words, is Sun's output "positive" if its gravity is factored in ...
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How do we contain nuclear fusion?

I understand that here on earth we create fusion at temperatures that are much hotter then our sun. What I want to know is how we contain those high temperatures safely. Also if any one can give an ...
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Does converting rest mass to energy instantly change the gravitational attraction it exerts?

Let there be two hydrogen atoms having 1.1 mass each. We use solar fusion to convert the two hydrogen plasma to helium with a mass of 2 and 0.2 gamma radiation. Before the fusion process gravity was ...
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Fusion methodologies

Forgive my naivety but it seems to me all the attempts to create useful fusion concentrate on high temps or high pressures or both and samples of fusible material consisting of multiple nuclei. Is ...
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59 views

Biggest Fundamental Force Examples? [closed]

I know that this question sounds confusing but listen well, What I am asking which phenomenon that happens anywhere in the universe that best represents the four fundamental forces. Nuclear Fusion, ...
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1answer
56 views

Using coil gun make two mass of lithium deuteride collide and start nuclear fusion

We already have hydrogen bomb, why controllable nuclear fusion so difficult? And why controllable necessary? If we can detonate a tiny hydrogen bomb, we can collect the energy, like laser nuclear ...
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Nuclear Fusion Proton-Proton Chain

When hydrogen nuclei are able to overcome the coulomb forces, two protons collide. As a result, one of them decays into a neutron and a positron and electron neutrino are emitted. However, isn't mass ...
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auto-refilled nuclear fusion generator [closed]

I read in a science article that in a nuclear fusion reactor, the energy we bring to the reaction is multiplied by a coefficient q. This coefficient needs to be at a certain level (around 7 if my ...
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Why the nuclear fusion 6Li+D and 7Li+P reactions happens 10 time less than H+11B?

The first two reactions generates 2 alphas and the boron one generates 3, but boron has 2 more protons than lithium so should repels more to hydrogen. I suppose is a question of nuclear states, but ...
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Form of energy release

I know that fusion and fission can be esothermic processes if they happen between the "right" elements (meaning, indicatively, lighter/heavier than iron respectively). I always thought I got this ...
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2answers
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How is fusion reactor fuel initially accelerated?

If, in a nuclear fusion tokamak reactor, you start with neutral fuels, how do you accelerate the atoms fast enough to start the reactor? Or do all of the particles have to ionized to begin with?
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Ideal MHD stability with a Fourier analyzed perturbation

I'm learning through the basics of ideal MHD instabilities and the textbook (Friedberg, Plasma Physics and Fusion Energy, 12.4-12.6) writes the linearized momentum equation in terms of the ...
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1answer
83 views

What is a quasi-axisymmetric stellarator?

I know that a tokamak is a donut shape fusion confinement device with an axisymmetric magnetic field configuration. The stellarator is similar but its field configuration is non-axisymmetric. I've ...
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Does a fusor emit dangerous radiation?

I noticed some online videos where people have built these things in their house or garage. Is it dangerous to do so? The high voltage appears to be a potential hazard, but what about radiation -- ...
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Does a high-velocity ion being neutralized by an electron emit Brehmsstrahlung radiation?

I'm curious about a point of the physics of Polywell electrostatic confinement fusion devices. One of the key claims made in the design is that by confining some "low temperature" electrons to a ...
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1answer
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CNO fusion using particle accelerator?

The CNO cycle is a catalytic fusion reaction that produces energy in stars larger than the sun. It converts four protons into a helium-4 nucleus using a cycle of carbon, nitrogen and oxygen isotopes ...
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1answer
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Are both ions and electrons assumed to be moving in plasma currents?

In a tokamak plasma, for example, an ohmic transformer is used to inductively drive current. In this scenario, is it simply assumed that the electrons are mobile and driving all the current in a ...
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What determines direction of plasma current in tokamaks?

Plasma current is used to ohmically heat fusion plasmas and provide stabilization of grad-B drift in tokamaks as the resulting poloidal motion of the charged particles results in the particles ...
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2answers
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Does Nuclear Transmutation release or take in energy?

I wanted to know whether the bombarding a particle to transmute it into another particle releases or absorbs energy. For eg, I wanted to know specifically for O-17 formation: I found a question which ...
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Would it be possible to use lasers to plug the end holes in magnetic mirror confinment fusion schemes?

My first thought was that the plasma being not very dense likely wouldn't adsorb much of the light but I think you could set up symmetrical gain chambers so that any light going out one laser, and ...
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1answer
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When will hydrogen no longer be the most abundant nucleus?

In a recent question, we learned why hydrogen is currently the most abundant nucleon or element in the universe. Here I ask a follow-up: For how long will hydrogen be the most abundant nucleus? It ...
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2answers
256 views

Is there evidence of gas ever forming a black hole without being a star first?

Here's my general understanding of how gas particles form a black hole: 1) Gravity pushes gas particles together. 2) These fast particles create heat (from friction due to them rubbing together?). ...
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Triple-alpha reaction rate

I'm trying to find a general equation for the fusion rate of the triple alpha process. I found this equation: The rate of energy generated by this process as a power law in $T$, centered around $10^...
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Laser Powered Fusion Reactor

I've been doing research on Helium-3 fusion (2H + 3He -> 4He + 1p) and was thinking about how to overcome the Coulomb Barrier for this reaction, when an article from a science news website popped up ...
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How do fusion reactors deal with blackbody radiation?

The plasma of the ITER reactor is planned to be at 150 million K. Using the Stefan-Boltzmann law, setting the surface area as $1000\,\mathrm{m}^2$ (the plasma volume is $840\,\mathrm{m}^{3}$ so this ...