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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197 views

What would happen if you detonated a nuclear bomb inside a tank of liquid hydrogen?

Say you had a large bomb - take the 50 megaton Tsar Bomba. You then proceed to place it in the center of a spherical tank containing liquid hydrogen, and then detonate it. Could you start a fusion ...
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133 views

Nuclear fusion/fission vs. magnetic characteristics of Iron

Is the fact that Iron is attracted to magnets in any way related to the fact that it is also the element occupying the singular periodic table position where the chains of nuclear fission and fusion ...
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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
318 views

Kinetic energy required for a fusion event

This question is given in my textbook: Consider the radius of both deuterium and tritium to be $2.0 fm$. What is the kinetic energy needed to overcome the coulomb repulsion between the two nuclei? ...
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1answer
910 views

Ohmic heating in a fusion plasma

In a microscopic classic picture, ohmic heating occurs due to collisions. Let's start with the simplest case: a cooper wire and a battery that induces a current. Electrons start flowing and the energy ...
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2answers
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Could focused sunlight ignite a pellet of lithium deuteride?

This is a basic question, but it something I have been wondering ever since I learned about inertially confined fusion. In the ICF reactor configurations I am aware of, the drivers that are used to ...
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1answer
653 views

Energy needed to overcome the coulomb barrier

I am in my first year of college and doing an EPQ type project on nuclear fusion and am wondering about Coulomb's Law. I am looking into the force experienced by a particle due to the Coulomb force ...
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Can the fusion and fission of a group of atoms occur infinitely? [closed]

Is it possible to split a nucleus and put it back together? If so, is it feasible to do it an indefinite number of times, i.e. without them wearing out or failing to stick together once again?
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217 views

Is the Dynomak concept physically sound?

I recently stumpled upon this article: Inside the Dynomak: A Fusion Technology Cheaper Than Coal Is the Dynomak concept physically sound? What kind of challenges could it run into? Can it make ...
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1answer
885 views

Why does resistance decrease as the temperature increase in plasma?

I am writing about Ohmic heating as a heating method for fusion for a class in school. But I wonder why the resistance decreases as the temperature increases in the plasma? This seems odd because ...
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1answer
64 views

Ion acoustic waves in a deuterium plasma?

Has anyone ever experimented with inducing ion acoustic waves in a deuterium plasma? Perhaps to observe the phenomenon of Landau damping? Or to heat the plasma for fusion reactions to occur? And, ...
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Calculating the energy produced in watts in Alcator C-Mod

I calculated the energy in joules that a deuterium-tritium fusion reaction releases and found 2.81829046e-12J. I then read on some MIT articles that the Alcator C-...
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Nuclear Fusion Reaction [closed]

My question is about the energy released in a nuclear fusion reaction, consider: $\mathrm{{^{2}_1H}} \ + \ \mathrm{{^{2}_1H}} \ \rightarrow \ \mathrm{{^{3}_2He} \ + \ n \ + \ 3.27 \ MeV} $ ...
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How ready is the current fusion reaction technology for the mass production of electricity?

Could you give a clear summary statement about the maturity of the controlled fusion reaction technology and its readiness for the mass production of electricity? There are many articles on internet ...
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Nuclear Fusion: Why is spherical magnetic confinement not used instead of tokamaks in nuclear fusion?

In nuclear fusion, the goal is to create and sustain (usually with magnetic fields) a high-temperature and high-pressure environment enough to output more energy than put in. Tokamaks (donut shape) ...
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1answer
50 views

Can stellar nucleosynthesis processes other than deuterium-lithium, i.e., oxygen-burning, take place in a reactor?

It is known that gravitational confinement and supernovae facilitate the synthesis of heavy nuclides; and, that magnetic confinement is thought to facilitate the deuterium-lithium fusion in human-...
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1answer
144 views

Were the 1st generation stars low or high-mass stars?

I have been taught that the first stars to be "born" could not use the CNO cycle to fuse Hydrogen into Helium as there were no elements heavier than Helium and a bit of Lithium to use in those ...
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Is there a distinct size limit between planet and star?

This question was inspired by: This recent article about an exoplanet "10 times the size of Jupiter" Prof. David Taylor's website about the "Life and Death of Stars" (in particular, the first page's ...
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Why nuclear fusion deliver energy instead of taking? [duplicate]

In nuclear physics, when you break eg. a nucleus of Uranium, some neutrons are liberated, and the original atom degrades to a lighter element. The energy that was used to keep these subatomic ...
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4answers
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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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Could we create our own mini star?

If NASA were to work together with other space programs, could we accomplish the task of creating a mini star in the future. It wouldn't be huge, under a mile in diameter. We could make a core of ...
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1answer
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Why all the orifices, protuberances, hinged/bolted panels, etc. on a stellarator?

My question was inspired by this one - in particular the image it has (also shown here): Why does the external casing of the Stellarator (in particular, the Wendelstein 7-X shown in the above image) ...
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What is the theoretical efficiency of fusion?

What is the theoretical limit of the amount of energy that can be extracted from a fusion reaction? I am not talking about the practical efficiency of a reactor, but rather what fraction of the mass-...
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1answer
141 views

Why is there a difference in measured binding energy vs formula for binding energy? [closed]

I have a question about calculating the energy release from a fusion reaction. With parameters I have been supplied the liquid drop model semi-empirical binding energy formula gives the wrong answer. ...
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1answer
67 views

Proof of actual collisions in beam collision fusion?

An enormous number of experiments have been done over the years where the experimenters collide nuclei from a particle accelerator with a target. Typically nuclear reactions take place with a very low ...
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Ways to make a star go supernova? [closed]

Asking for a fictional storyline. Say a type iii civilisation on kardashev scale want to make a star go supernova. Then what are the possible ways to achieve this? The said star being massive ...
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1answer
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Logic behind Coulomb explosion fusion?

Many experiments seem to have been done where the experimental setup consists of an extremely short, but intense laser pulse, impinging on e.g. deuterated plastic of some sort or some "jet" of nano ...
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1answer
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What is the critical electron density in a plasma?

In the article Ion Acceleration and D-D Nuclear Fusion in Laser-Generated Plasma from Advanced Deuterated Polyethylene by Lorenzo Torrisi, the author mentions a critical electron density on page 17057....
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Can a fusion bomb make electricity? [closed]

Would blast energy remove a single piece of pre-cut earth above an underground explosive? Could you then break apart the piece of earth and lower it back into the cavity as a way of generating power? ...
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Does 60kg of fusion fuel produce as much energy as 400 kilotonnes of coal?

Several people, including Fusion for Energy have posted this infographic: To meet the energy needs of a city of 1 million people one would need: Either 250,000 tonnes of oil Or 400,000 ...
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Distinguishing an underground Hydrogen bomb test from a fission bomb explosion

A related question is Hydrogen bomb radiation output, but my question is based on the seismograph data (or any other data) possibly producing a distinctive pattern. Is it possible to tell the ...
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1answer
63 views

Stellar Ignition and Neutrino Energy

My question has to do with the following two pieces of information: When Fusion Ignites and a star is born, according to the Proton-Proton Chain, a positron and a neutrino are released when one ...
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How fusion reactor could be operated on space craft? [closed]

Considering that space craft uses engines only during acceleration and deceleration, how fusion reactor will be operated? For example: it will be started / stopped for each maneuver will be working ...
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Has a nuclear explosive ever been detonated by another nuclear explosive? That is, a “secondary nuclear explosion” [closed]

So the question is this: Even though thermonuclear explosives(those with 2++ stages) are complex devices that require symmetrical compression in order to detonate(the fission stage). If, say, a ...
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Could CPA lasers be used to produce a Pure Fusion Weapon?

In particular, has there been any experimental testing of using the Chirped Pulse Amplification (CPA) technique to ignite a fusion pellet in the first place. If so, have any of the experiments yielded ...
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1answer
159 views

High temperatures in Nuclear Fusion

So, during nuclear fusion, hydrogen-1 nuclei fuse with hydrogen-2 nuclei. Given that these nuclei are both positively charged, that means that they repel, and thus have a positive Coulomb Potential.($...
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1answer
210 views

Can efficiency of fusor be improved by scaling up?

Fusors are very inefficient, among other reasons because the ions have to be decelerated and accelerated every time they fly out of the fusor, while radiating the energy out. However, what if we could ...
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Can nuclear fusion alone account for the energy output from type 1a supernova?

Unlike other supernova, which can vary in their size, Type Ia supernova are all about the same size. This is due to the fact that they are caused when a white dwarf star gains enough mass from its ...
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How exactly is fusion possible?

It is a very dumb question but, I once read that fusion was possible when the wavefunction that describes the position of a particle overlaps with the wavefunction of other particle, but I think I don'...
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How to calculate the life expectancy / fusion rateof a star? [duplicate]

If I have the mass (and if needed, the atomic mixture) of a star before it forms, is there some mathematical way to calculate how fast the star will burn through its contents and die?
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Why does fusion use mass for energy?

I have the basic idea: for small nuclei the mass of product is less than the mass of the individual pieces, this mass is released as energy via $E=mc^2$. But why do nuclei use the mass for energy? ...
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Would a pin head heated to 15 million degrees Celsius kill everyone in a 1000 mile radius?

The YouTube video How Hot Can it Get? contains, at the 2:33 mark, the following claim: A pin head heated to 15 million degrees will kill everyone in a 1000 miles radius. On what basis can this ...
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1answer
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What is the shortest duration fusion reaction?

In a tokamak fusion reactor fusing hydrogen nuclei what is the shortest duration experiment that successfully fused nuclei. Is there a database with fusion reactions and their duration.
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1answer
200 views

How long does it take for fusion to occur in a tokamak?

Once the plasma is in the tokamak reactor how long does it take until fusion starts to begin? I found that it must reach 150000000 degrees so, how long does it take for the plasma to reach this ...
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1answer
4k views

How many times does plasma do a full loop tokamak before fusion?

From this photo I assume the plasma is also moving in a loop through the reactor due to it being a charged particle. I have been trying to find a speed at which it does this but couldn't and neither ...
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4answers
1k views

Where does mass deficit energy go?

I get the idea (at least, as much as a layperson can) that a helium nuclei has less mass than the sum of its parts. That mass deficit is turned into energy. At this stage I feel like I've heard two ...
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Can air plasma ions in a fusor fuse?

I know that hydrogen ions will fuse in a fusor but what about air ions? Can air plasma ions in a fusor fuse? https://en.wikipedia.org/wiki/Fusor, if so, under what cicumstances, and how would I ...
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How to calculate the bremsstrahlung limit in the fusion triple product diagram?

The fusion triple product is a commonly used figure of merit to quantify the progress in fusion research, it is the product of plasma density $n$, temperature $T$ and energy confinement time $\tau_E$....
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At what rate do I need to accelerate for my car to become a fusion reactor?

I was sitting on the bus on my way home, and this popped into my mind. As a car accelerates, the air pressure at the back of the car increases as air is pushed back due to inertia. This pressure will ...
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Fusion reactor with lasers and magnets

Both magnetic and laser fusion reactor work to a point, but what would happen if you had magnets and then lasers to heat up the pelts and/or plasma? And what would be the best the best way to achieve ...

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