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.
Hi there,
Sorry if thisis a stupid question its just been bugging me for a while and I am not a scientist as such so need help with the answer...
nuclear fission is where two atoms collide and release energy yes?
nuclear fusion is where two atoms combine to release energy and a new isotope...
Hi, I'm in my final year at an Australian high school and I plan on completing at Bachelors in Science Majoring in Physics as my undergraduate course. My career aspiration is one day work researching nuclear fusion, though I am happy to work with fission reactors, they're just not my first...
Homework Statement
During fusion of hydrogen to helium, 4 billion kg of matter are converted
to energy each second. What fraction of the Sun’s total mass is lost each
year to this process?
Homework Equations
None.
The Attempt at a Solution
First:
Convert how many seconds are there in a year
1...
I am currently in my first year of undergrad taking general science course classes with an undeclared Major. My dream is to work with Nuclear Fusion reactors, and i am at a bit of a loss at choosing Majors. Should I make my concentration "Applied physics specializing in Nuclear Engineering(or...
I am interested in doing research in controlled nuclear fusion , i am doing my electrical engineering 4th year in India. Since no college in my country offers post graduation in fusion related fields , i have decided to do M.Tech in Nuclear science and technology in Indian Institute of Technolgy...
A basic question for which I could not find any answers on the internet:
What factors do determine whether the fusion results with a He-4 and gamma rays, H-3 and proton, or He-3 and neutron? If it is random, are there any methods to predict the rations of these reactions?
Thank you.
Do you know of any promising concepts for small scale fusion reactors (for electric power production)?
I'm thinking of something the size of, say, a train car or even smaller.
Certainly fission is a prime example of entropy. But what about fusion? Doesn't fusion look like a process that goes from a disordered state to an ordered one? Out of chaos comes order!
What is the general difference between the two (for someone who is still new to nuclear physics) and which one produces the highest net energy? Which of these has the highest potential for the future?
I'm only beginning to scratch the surface of higher level Physics and, despite my usual haunt being the EE area, I enjoy reading the responses and discussion in this section of the forum.
I was talkin' to a friend about Fusion power and he asked me why it wasn't used instead of Fission. Now...
When doing an experiment to find the specific latent heat of fusion of liquid nitrogen, you find that 100 kJ of heat must be removed to freeze 3.8kg of nitrogen at its freezing point. What value will you get for the specific latent heat of fusion of nitrogen?
Power=100kj
M=3.8kg
I don't...
I came across these slides http://hedpschool.lle.rochester.edu/2009SummerSchool/lectures/Key.pdf which say that the main problems with Fast igniton fusion are
1. Compress DT fuel to high ρ, ρR around cone tip; cone tip must survive Gbar implosion pressure
2. Relativistic laser interaction...
I am doing a high school research project on nuclear fusion and i just wanted to double check if my understanding of the role of binding energy in fusion reactions was correct.
So we add energy in the form of heat to a tritium atom of mass "3" approximately and deuterium of mass "2" , this is...
Hey guys,
So, I'm writing a screenplay about space travel. I've been thinking of using nuclear fusion as the method of space travel. I've read it's a viable option. But, I don't know much about nuclear fusion.
I know cold fusion is, at this point, a near-impossible option. But is it true...
Homework Statement
You are required to calculate the efficiency of an ice-making machine that takes in water at a temperature of 16°C and produces ice cubes at a temperature of -6°C. Water is taken in at the rate of 1kg every 5 minutes and the input power to the machine is 300W. The Specific...
Ok so I recently read this article (http://www.extremetech.com/extreme/184280-focus-fusion-has-cheap-clean-earth-saving-fusion-power-been-right-under-our-noses-all-along). This gave me a few ideas and a few questions. I would like to create a smaller version of this setup to fuse deuterium into...
I am an electrical engineering student doing my third year. I am interested in doing research in making fusion energy a commercial energy source by doing research in current techniques and also interested in creating new techniques for making fusion process continuous and efficient than current...
I am trying to determine whether a burn would propagate faster through hydrogen or helium.
My initial guess is helium due to the higher mass. I also think this is true in stars. Anyone have an idea on burn propagation and how different masses of material would affect it?
Is my first...
Hi,
Three questions to forum about something I have been wondering about on antimatter:
Can antihydrogen fuse to make antihelium through an antiproton-antiproton chain similar to how protons fuse to make helium in the Sun?
If so, like nuclear fusion with matter, does nuclear fusion with...
Was this technique ever demonstrated experimentally, or it could be regarded as practically failed theory?
https://lasers.llnl.gov/science/ignition/fast-ignition
A few years back I started a thread to make the point that there is a common misconception about main-sequence stars that their fusion rate sets their luminosity, in the sense that to know what the luminosity of the star will be, you need to know what the fusion rate is. In particular, you...
When using ice to keep a room (or in my case, a cooler) cold, one would want it to have a high specific heat capacity and a high latent heat of fusion, so that it would absorb a lot of energy as it melts. Basically, so that it melts as slowly as possible.
I know that adding salt to road ice...
If I was going to build a fusion device for energy production I would build a cylinder filled with fusion fuel and the fusion would happened in the center. First it would be hard to start the fusion with relatively cold fuel. After a while of heating, the surrounding fuel would be hotter even if...
Hi everyone,
This is a question about conformal field theory. Even though it is not directly about beyond the SM, it seems like an appropriate place to ask since it is an important tool in string theory.
I am confused by the fusion rules \phi_i ~ \phi_j = N^k_{ij} \phi_k
(where as...
I have a problem reconciling something. According to Newton's shell theorem, at any point within a solid sphere, for the purposes of calculating the gravitational force exerted on you, the mass that is outside your own radius to the center can be ignored since it cancels out, and the net force...
Hi guys, I'm pretty new to the site and I have a few questions, but I'll start with the most imporatant ones or at least the ones I would like answered first.
Anyway so my understanding is that in a thermonuclear weapon the large majority of the explosive power comes from the fission reaction...
Homework Statement
The energy output of an average person is about 121 Watts. Suppose the average human has a mass of 80 kg and it could run on fusion power by converting only .7% of its mass into energy.
1) how much energy would be available to the body through fusion?
2) How long could the...
This is a total newb question but please explain. If nuclear fusion is occurring during a hydrogen bomb explosion, then why is it said that more energy is needed catalyze fusion than will be produced during the reaction - H-bombs seem to blow that theory out of the water. (no pun intended) :-p
I'm looking for some input on this. Wisconsin has the better programs for MHD theory, CFD, and my undergrad advisor told me IHO it has the best plasma physics program period. However Michigan offers more options in applied plasmas in areas other than fusion energy. Honestly, I don't know if...
I am currently studying A level Physics. I understand that, in a nuclear fusion reaction, the mass of the nucleus we end up with is smaller than that of its constituent nuclei, so Δm is negative and so energy is lost in huge amounts. But what about a nuclear fission reaction? The mass of the...
I'm aware my following thoughts are highly speculative at best, i just wish to be explained, are they total magic, do they have anything common with reality, what can be their Mohs scale level?
I thought about a story, where people fused their brain with nanobots, while they still think like...
I was wondering whether thermonuclear fusion could be achieved in accretion disks around black holes, or even neutron stars/white dwarfs. Seems like, in AGN at the very least, you would easily get the kind of temperatures and pressures necessary for thermonuclear fusion, perhaps even synthesis...
Hi there,
When an alpha particle is formed inside a nucleus by binding together is this essentially nuclear fusion occurring?
Why is this more likely to happen in a large nucleus than a small one?
Thanks
I'm taking high school physics, and I've had problems in the past with flat out errors in my textbook (I've brought them up here). It's incredibly frustrating when your trying to understand something.
Anyways, I need to know which is right:
The text in my book goes through to explain...
Hello, this is my first post(so, hopefully I'm not breaking any decorum).
Something that I've always been puzzled about. I understand that a star will keep fusing elements until it hits iron. What I'm curious of, is why? Why does iron take so much more energy to create fusion than other...
Homework Statement
"Assuming that the incident deuteron has sufficient energy, why is the reaction d+d \rightarrow He^{4}_{2}+\pi^{0} not allowed?"
Homework Equations
The Attempt at a Solution
I've gone through the various conservation laws that apply in a strong reaction...
Homework Statement
A 100g (.1kg) cube o ice at 0dC (d=degrees) is placed in 1kg of water that was originally at 80dC. What is the nal temperature of the water after the ice has melted? Answer: 65.5dCHomework Equations
Lf = Q/m
Q=(DelT)mCThe Attempt at a Solution
At first I looked up the latent...
Hi!
I am just asking a question a friend of mine asked me: "When will fusion work?"
I personly think it is not a question of if as much a question of when.
I am a little bit lazy here but I have read the ITER information a while ago and I think they said very confidently that this new Tokamak...
Homework Statement
This is for my intro to General Relativity class, using Hartle's text Gravity: An intro to Einstein's GR.
12.1 "How many protons must combine to make one He nuclei every second to provide the luminosity of the Sun? Estimate how long the Sun could go on at this rate before...
Hi,
I'm doing some coursework on nuclear fusion, and am trying to calculate the energy released by fusing a tritium and a deuterium atom together. I used the equation:
( Σ mass (reactants) - Σ mass (products) ) x 931.5 MeV/amu = Binding energy.
and Deuterium + Tritium = Helium +...
Hi,
I'm doing some coursework on nuclear fusion, and am trying to calculate the energy released by fusing a tritium and a deuterium atom together. I used the equation:
( Σ mass (reactants) - Σ mass (products) ) x 931.5 MeV/amu = Binding energy.
and Deuterium + Tritium = Helium +...
Coils produce a magnetic field which confines a big plasma ball.
The magnetic field is rapidly increased which makes the plasma ball implode.
In the compressed state fusion happens. The plasma ball explodes
and compresses the surrounding magnetic field.
This produces more induction in the...
Scientists at Lawrence Livermore National Laboratory used the NIF ( National Ignition Facility ) laser to reach encouraging progress toward ignition From "The Independent" newpaper serving Livermore:
http://www.independentnews.com/news/article_792110c0-2c5b-11e3-846e-001a4bcf887a.html...
Hi everyone,
I am currently applying to graduate schools in nuclear engineering. I am applying to some top 10 schools and also some lower ranked ones as safeties. However, my fear is that if I am not accepted to a top ten school I will have to attend the safety schools. I am not particularly...