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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2answers
44 views

Could you know in advance specifically when a star will go supernova?

I've been thinking about star trek 2009 and star trek Picard in which they happen to talk about a sun inside a fictional solar system which goes supernova destroying a particularly important planet to ...
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1answer
59 views

Why is there more lead and mercury in the universe than gold?

I am watching a Science Channel program on the collapse of massive stars and it got me wondering... What is the distribution of heavier than iron elements in the universe. (It is my understanding ...
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2answers
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Is there anything quantum mechanical related to Fusion/Fission? ( Instead of special relativity)

Fusion/Fission is always accompanied by the special relativity relationship of $E=mc^2$. Yet there are atoms that are undergoing change, and that should be in the realm of Quantum Mechanics. Maybe in ...
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1answer
12 views

Electrostatic Plasma Confinement Fusor

I wish to build a Fusor. Now, in order to build it, a high voltage is required generally achieved through Neon Sign Transformers. If I want to achieve voltages 25 kV or more, how am I supposed to do ...
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4answers
12k views

Can open, unsafe nuclear fusion reaction burn the atmosphere?

I happened to hear people saying that the nuclear fusion bomb tests could set the atmosphere on fire. I have some serious doubts about that - but I have no facts. Nuclear fusion reaction requires $15*...
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8answers
6k views

Why doesn't the nuclear fusion in a star make it explode?

I have a rather naive question. In stars such as the Sun, what prevents the whole thing exploding at once? Why is the nuclear fusion happening slowly? I can only assume that something about the fusion ...
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1answer
17 views

Is heating plasma the only way to initiate fusion?

I was looking at why fusion reactors need to get so hot and the internet said that it needed the momentum to overcome the repulsive forces of two atoms. Is heating the atoms the only way to give it ...
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1answer
36 views

Minimum amount of Tritium for fusion reaction producing Tritium [closed]

I'm not studying physics. I only worked with basic dynamics and have no idea how to calculate this. It's likely that the answer to the question I'm asking is nonsensical, but, from my point of view, ...
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2answers
73 views

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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Stellar nucleosynthesis

I would like to learn more about fusion in stars. The question I have is whether there exists a graph showing exactly which elements take part in the reactions. Here, I managed to find some data ...
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1answer
31 views

Positron-electron anihilation in the Sun

As 75% of the Sun is Hydrogen and 25% Helium and the latter derives from 4 hydrogen atoms where half of protons that formed neutrons expeled positive charges as positrons that anihilated with nearby ...
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1answer
42 views

Could one, with enough electricity to spare, use particle accelerators to mass produce heavy elements

If electrical, and economic limitations are ignored, would it be possible for a civilization to mass produce many millions of tonnes of useful heavy elements using particle accelerators? Could they ...
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1answer
17 views

Stabelizing Quarks?

I have been recently looking into something called Quark Fusion. The whole thing is a theoretical concept of colliding heavier and lighter Quarks to produce energy. There is one thing to it tho. It is ...
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0answers
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In the middle of depletion layer of reverse biased p-n junction is the electric field almost zero?

My textbook states: Due to reverse biasing the width of the depletion region increases and current flowing through the diode is almost zero. In this case electric field is almost zero at the ...
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2answers
80 views

Is it right interpretation to interpret $E=mc^2$ using potential energy?

I am wondering that it is the right interpretation to interpret $E=mc^2$ with potential energy. What I mean is this: When I studied nuclear fusion, there was missing mass. The hydrogen's nuclear ...
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2answers
89 views

How dense could an Earth-sized planet be before beginning to undergo fusion?

I'm trying to figure out the maximum possible density for an earth-sized planet before it would become an earth-sized star. To try to figure this out, I found a reference star, VB 10, known for being ...
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1answer
9k views

Reason why stars do not produce elements heavier than iron

In his book "Origins", Neil deGrasse Tyson says that "if you seek to split iron nuclei apart, you must them with additional energy. On the other hand, if you combine iron atoms they will also absorb ...
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53 views

Does the speed of light determine the energy released in fusion reactions?

The Openstax Astronomy book talks about stars converting mass into energy via fusion reactions: So far, we seem to have a very attractive prescription for producing the energy emitted by the Sun: “...
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3answers
52 views

How can heavier elements be made from hydrogen atoms?

In a JRE podcast from a few years ago, talking about the idea of a universal constructor, Sam Harris said that we could go to a near-vacuum area of deep space, collect nothing but hydrogen atoms, ...
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5answers
12k views

Why isn’t CERN afraid of a fusion reaction in the LHC?

Given that they can reach terrifying energies and temperatures, why isn’t fusion of protons a concern? After all, they start with a plasma and ram protons into each other. At some point the strong ...
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1answer
58 views

Why do tokamaks and most other fusion reactors use neutral plasmas?

Most experimental fusion reactors use quasi-neutral plasma as the working substance. However, there are numerous advantages to using a non-neutral plasma: Ease of confinement. Pure proton gases have ...
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1answer
33 views

Can gamma rays be blocked or redirected by magnetic or electromagnetic fields?

I've been interested in fusion research for a while now and found that reactions such as the proton-proton cycle produce a lot of gamma rays which require large quantities of water or lead to shield ...
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2answers
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Does a fusion reactor have a cool-down period or can it operate continuously

Can a fusion reactor like ITER maintain it's fusion reaction and generate net output electrical power continuously; so long long as fuel is supplied, or does the reactor need to be shut down ...
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4answers
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Why can't Iron fusion occur in stars?

It is said that iron fusion is endothermic and star can't sustain this kind of fusion (not until it goes supernova). However star is constantly releasing energy from fusion of elements like Hydrogen ...
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2answers
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Why do only red dwarf stars have convective currents?

Stellar models indicate that red dwarfs less than 0.35 M☉ are fully convective.[3] Hence the helium produced by the thermonuclear fusion of hydrogen is constantly remixed throughout the star, avoiding ...
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3answers
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Requirements for hydrogen fusion

What are the requirements for hydrogen atoms to go through fusion? Is it a ratio of heat to pressure or are there specific heat and pressure values that must be met (per atom or per mole?) Are there ...
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4answers
880 views

Why can't we harness the energy from neutron + protium = deuteron reaction? [closed]

The answer to this physics se question, established that 2.2Mev (Mega electron volts) of energy is emitted as a gamma ray photon when the hydrogen atom nucleus oka protium absorbs a slow moving free ...
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2answers
80 views

Why does the sun have the Fe?

I read the information about 'Abundance in the sun for the elements'. There are a lot of elements in the Sun. I thought 'how is it possible to exist Fe, Au, and so on in the Sun ?', but I couldn't ...
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1answer
55 views

How much energy is required to fuse two protons? [closed]

What is the kinetic temperature required to fuse two protons in a plasma? How much energy does it release? What are the products of the fusion reaction?
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1answer
35 views

Where does the negative electrode come from in an HB11 fusion reactor?

I'm an electrical engineer. Throughout my education, I was taught that current always has a return path. This understanding applies to everything. Batteries use an electrolyte to strip electrons ...
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1answer
47 views

In fusion inside stars (sun) or very hot gasses, how do the electrons get bound and what about tritons and D-T vs D-D fusion?

Most texts I've read focus on just the nuclei to begin with, but eventually start talking about Helium (or other) atoms and isotopes. A few aspects aren't clear to me and I'd be grateful for some ...
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1answer
31 views

Does the proportion of strong nuclear force in a star change during nuclear fusion?

I read that the SNF accounts for 99.9% of the mass of an atom. So if 4 hydrogen atoms become 1 helium atom during nuclear fusion does that change the proportion of SNF as we have 4 SNFs becoming 1 ...
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2answers
1k views

Is neutron-neutron fusion viable?

Do I get unusual baryon maybe like pentaquark or just a pair of conjoined twin that is very unstable?
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0answers
51 views

Theorical efficiency of Chirped Pulse Amplification HB11 fusion reaction

I read that scientists finally reproduced a more efficient fusion with a novel approach. They accelerate hydrogen inside a pellet with a LASER. A single H atom produces three $\text{He-4}^+$ nuclei. ...
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Why do stars get bigger and brighter when older?

As stars age, the concentration of Hydrogen in the core decreases which lowers the power output, causing an imbalance between outward radiation pressure and inward gravitational pressure. This causes ...
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3answers
2k views

Can the High beta fusion reactor work?

Are the claims made about the http://en.wikipedia.org/wiki/High_beta_fusion_reactor realistic? Can such a small fusion reactor really work?
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50 views

Why is the $\rm CNO$ cycle is much more efficient than the $p$-$p$ cycle?

Why is the $\rm CNO$ cycle is much more efficient than the $p$-$p$ cycle?
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2answers
77 views

Can artificial fusion have the same power density as in Sun's core?

I recently read about solar core, and found that the power density is only 276.5 watts per cubic meter. This seems rather low to me, but on the other hand the Sun is an enormous object, so the total ...
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5answers
145 views

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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2answers
76 views

How do we know fusion energies?

Crucial to our understanding of stellar evolution is the energies involved in nuclear fusion reactions. How do we know those energies? How do we know which fusion reactions take place, at which ...
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1answer
61 views

What can be learned from Wendelstein 7-x experiment?

This experiment achieved a stable plasma for 26 seconds. What do we learn from it in general(why it was done)? and specifically about the possibility of achieving positive energy flow ($Q>1 $) by ...
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1answer
34 views

Using a Neutron Poison In $D$-$T$ Fusion Reactors to Capture Neutrons

One of the major problems of the $D$-$T$ fusion reaction is that it releases a 14MEV neutron. In large numbers, these neutrons irradiate the chamber walls and wreak havoc on the metallic lattice, ...
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1answer
24 views

Can a Magnetic Confinement Fusion Tokamak generate An Axial Vertical Field? [closed]

A question from a complete novice: Perfectly aware that tokamaks confine plasma in a toroid, could they potentially generate an axial vertical electro-magnetic field as a side-effect, or is it ...
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7answers
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As neutrons are more massive than protons, does the Sun increase its mass while fusioning elements?

Where is the mass coming from when neutrons are produced from protons in the Sun? If a positron is made, will it possibly annihilate with an nearby electron?
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Why is the weak force the main limiting factor when it comes to the $p$-$p$ fusion chain, instead of the quantum tunnelling effect?

For the $p$-$p$ fusion reaction chain occurring in the sun, why is it that the main limiting factor placed on the time scale of the initial proton proton fusion into helium due to the fact it is a ...
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5answers
10k views

How much iron would I have to shoot into the Sun to blow it up?

My understanding--though it's from a Science Channel show so I'm not sure if it is correct--is that there is a fusion reaction happening in the center of the sun. Atomic nuclei are being created and ...
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1answer
89 views

Why is humanity investing so little on fusion research? [closed]

Optimists expect fusion industry to be a reality in 2080 to 2100. Fusion means clean and unlimited amount of energy, it is the fuel of the universe. Fusion will solve most of our time problems ...
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0answers
15 views

How useful could neutrons as energy directors in fusion (similar to laser-accelerated electrons)

If you directed fast,'hot' neutrons towards a small amount of homogeneously mixed fusion fuel at a point, is fusion likely where the involvement of the neutrons need only be in providing energy and ...
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'Forces' enacted by hot neutrons in fusion bomb - Pauli exclusion

Are Pauli exclusion 'forces' on a neutron 100% electromagnetic (Lennard-Jones seems more acute relationship compared to electrostatic force) If so does that neutrons have two forces between them - '...
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1answer
46 views

Can the fusion of deuteron-like nuclei form a new type of periodic table

In late 2019, The Indian Lattice Gauge Theory Initiative, theorized the existence of exotic particles, "which can be formed through the fusion of heavy baryons, similar to the formation of nuclei of ...

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