Science topic

Nuclear Fusion - Science topic

Thermonuclear reaction in which the nuclei of an element of low atomic weight unite under extremely high temperature and pressure to form a nucleus of a heavier atom.
Questions related to Nuclear Fusion
  • asked a question related to Nuclear Fusion
Question
4 answers
"For the first time ever, US scientists at the National Ignition Facility at the Lawrence Livermore National Laboratory in California successfully produced a nuclear fusion reaction resulting in a net energy gain, a source familiar with the project confirmed to CNN.
The US Department of Energy is expected to officially announce the breakthrough Tuesday."
We all know what All Mankind have been through for the last decades, of which the climate change, energy crisis, etc. have always been pains in the neck. They directly or indirectly caused the shortage, inflation, supply-chain disruptions, regional/global economic crisis, or even escalated conflicts. Now, here comes a promising solution! (I personally suppose such an incredible scientific breakthrough deserves multiple Nobel Prizes!)
Assuming this major scientific breakthrough is solid and safe. Here come more interesting questions that are perhaps worth our attention and discussion:
1. How long would it take for this scientific breakthrough to be transferred to engineering deployment and energy usage in our daily life? < 10 years, 10-30 years, 30 - 50 years, or > 50 years?
2. What could you think of the pros/cons of this breakthrough (e.g., would it help mitigate the climate change, poverty issues, and regional/global conflicts over energy and resources? ), and what should be first done before the deployment? Legislation, international treaties, environmental protection, and/or etc.?
3. How do you think this breakthrough will accelerate all mankind to the Type-I Civilization (according to Kardashev Scale) and become a Spaceborne Civilization/Species?
4. What would be your thoughts/ideas/advice/suggestions/opinions on this breakthrough and how it can better serve all mankind?
Relevant answer
Answer
The previous comments well summarize some of the reasons the breakthrough doesn't indicate something that can address the climate problem. I listened Monday to Miles O'Brien, PBS's science expert, on the PBS News Hour discussing the fusion announcement. He ended a good description by saying an old physics joke was the statement:
"The actual practical use of Fusion Energy will take 20 years, and it always will !"
Unfortunately, I believe this is correct. When I came to Los Alamos in 1969 there was a magnetic confinement division called SYLLAC. There is now a related effort using a Tokamak machine in Europe, ITER, which is now about to go on line.
Several decades ago there was a LASER FUSION effort at LanL, smaller than NIF but a similar approach. The group leader of the group studying the theory involved was my best friend. This group was in one of my group's buildings. He told me they felt they had proved that the laser on a D-T pellet would not work in a practical energy production.
  • asked a question related to Nuclear Fusion
Question
3 answers
"THIS IS AN ABSOLUTELY SCIENTIFIC QUESTION"
The world witnessed nuclear fusion for the first time generating more energy than consuming (12/12/2022), at the Lawrence Livermore National Laboratory (California USA) which was indeed an extraordinary feat and allows nuclear fusion reactors!
In the figure, it is possible to see the tiny ball (a sphere of tritium and deuterium) that became a star on Earth.
And now? Which paths to follow? Inertial Fusion or Magnetic Confinement Fusion?
Whatever it is, it will be essential for human life.
Tell us your original opinion about it!
PLEASE ANSWER IN ENGLISH ONLY.
VERY IMPORTANT: Participate only if you are original, be yourself give your opinion, do not put links or texts from "Genio Google" or things found out there on the web! No one has any interest in stupid web answers, if that's the case, please be so kind as to ignore this debate! Also, don't post your hurts and hates, and don't deviate from the subject at hand, thanks.
Relevant answer
"Силы реакции a-излучения и лазерный термоядерный синтез"
Журнал технической физики, 49,(1),1979
А.В.Кулаков,А.А.Румянцев
Как учёные из разных стран приходят к одинаковым физическим результатам
Поделиться
  • asked a question related to Nuclear Fusion
Question
2 answers
I must measure temperature and ion density of 3-10eV plasma of hydrogen and boron at 5-50 pascals
As long as there are magnetic and electric fields, I can not install sensors inside
The first ionization energy of Hydrogen and Boron are 13.9eV and 8.3eV that corresponds to 91nm and 149nm, but there are no sensors for that frequencies
Relevant answer
Answer
Langmuir probe works in plasma exposed to magnetic field?
My plasma generates high density fusions, probe must withstands that
  • asked a question related to Nuclear Fusion
Question
3 answers
I am exploring using fluxes to remove oxidation from tungsten tiles used in nuclear fusion reactors. The flux should not be extremely corrosive (though we should be testing some options of that nature soon) and should work at reasonable temperatures (about 650C or below). Are there any such options already being used in some industry, or any potential ones that come to mind?
Thanks in advance for your help!
Relevant answer
Answer
I have used this flux to braze a sintered tungsten alloy (W97Ni2Fe1) but am sure it can also be used to braze tungsten carbide based cermets. It also works the other way around: fluxes for tungsten carbide must also work for metallic tungsten. Ultimately, the chemistry in both cases is the same: destruction of a tungsten oxide film.
  • asked a question related to Nuclear Fusion
Question
1 answer
My theory has G (Newton's Gravitational Constant) to be inversely proportional to the 4D radius of the Lightspeed Expanding Hyperspherical Universe (LEHU topology).
I need to simulate the Stellar Population under the epoch-dependent G assumption.
At this time, I consider that there should be a seed stochastic distribution of t_{ff} (which is inversely proportional to G*rho(0)
That distribution would be used over and over again to seed new stars at different epochs.
My problem is simulating the aging of previously triggered stars. For that, I need a consumption rate that is dependent upon GM. As far as I can tell, all star's processes are dependent upon the product and not just on the mass.
I welcome guidance.
Relevant answer
Answer
On the average, doubling the mass of a Main Sequence star increases its brightness by about a factor of 10, and reduces its Main Sequence lifetime by a factor of 5. For a rough but thorough discussion (intended for beginning college students), http://cseligman.com/text/stars/mldiagram.htm (The Mass-Luminosity Diagram and Main-Sequence Lifetimes) on my astronomy website.
  • asked a question related to Nuclear Fusion
Question
11 answers
I'm very skeptical about Quantum computers. First because of the Law of conservation of difficulties. If Quantum computers can solve problems impossible for classical computers (which are possible), then it must mean quantum computers are impossible to develop. Second, because for any meaningful real world applications that could revolutionize science you need a million qubits...but we are still at the 100 qubits mark (and 999,900 more to go). At this pace, Quantum computing will be the next nuclear fusion: chimeras that humans dream of but that never materialize.
What are your thoughts, professor?
Edit: "If Quantum computers can solve problems impossible for classical computers (which are possible), then it must mean quantum computers are impossible to develop"
If something is very hard to achieve but then quantum computers magically would be able to solve them, it means the difficulty has been transferred to the act of creating a quantum computer.
The harder the problems that can be solved by quantum computers, the harder it is to make one.
There is no free meal and no magic in technology...usually.
Relevant answer
Prof. Jose Risomar Sousa: Could yo please clarify the phrase "(which are possible)" in your sentence:
"If Quantum computers can solve problems impossible for classical computers (which are possible), then it must mean quantum computers are impossible to develop."
  • asked a question related to Nuclear Fusion
Question
5 answers
I need someone who is researching on Nuclear Fusion Reactor Technology...Is anyone there i want to join that researcher...
Relevant answer
Answer
Very sad to read useless answers and with so many recommendations from people who know nothing about the subject and pretend to know by doing mediocre research on the internet.
Yes, if something really was known about nuclear fusion energy, I would know that in 2021 ITER will be operational. And that the scientific advances for this are absolutely GIANT !!!
  • asked a question related to Nuclear Fusion
Question
13 answers
Suppose that you live in a large space shuttle, and there is no sun. How can you generate energy in order to supply your space shuttle and live? Is there any other way rather than nuclear fusion?
Relevant answer
Answer
You're absolutely right! A large nuclear submarine is largely submerged in travel for up to two years. Receives food supplies and two more years, without contributing.
Great example !!!
With fission nuclear reactor.
Regards,
Wiltgen
  • asked a question related to Nuclear Fusion
Question
3 answers
There are two types of hydrogen "burning" nuclear fusion processes in stars, namely proton-proton chain and CNO cycle. Has anyone looked at the feasibility of using the CNO cycle process in a tokamak to achieve nuclear fusion?
Relevant answer
Answer
In time: Fusion figure.
  • asked a question related to Nuclear Fusion
Question
5 answers
I measured more than one megatesla close to H-B11 nuclear fuel during nuclear fusions. Must be confirmed.
Now it is open the possibility that the matter comprises quantified magnetic fields only
Relevant answer
Answer
Thank you Ijaz. The present technology has very low fusion power. Also, the tokamak can be improved a lot, our Miranda design allow ignition grade reactors using low cross-section fuel as Hydrogen-Boron-11 as we stated in our simulations. We obtained also 120 teslas easily using nonstatic magnetic fields and also 15 kiloteslas in other structures. Also, if you read our last paper you can see that if aligned nuclear fusions, more than one mega teslas can be reached, but can not be done in a Tokamak structure that would implode.
  • asked a question related to Nuclear Fusion
Question
17 answers
We have been torturing Tokamaks for 70 years. We have no results. Now we are building ITER worth more than 20 billion euros. It will be experimental only.Maybe we should go back to basics? Understand that there is a charge, that there is a mass, how the alpha particle is arranged. We need to understand how the Sun works. Please read the book "Electromagnetic gravity. Part 2" in my profile. In the solar corona, the ions rush towards each other. Electromagnetic field provides pushing forces. Do you agree with my suggestions on this topic?
Relevant answer
Answer
Ijaz Durrani
Dear Ijaz,
I thank You so very much!
Yours
Valeriy Pakulin
  • asked a question related to Nuclear Fusion
Question
4 answers
The Big Bang theory proposes that the Cosmic Microwave Background Radiation (CMBR) is a flash of radiation from a process called recombination which occurred when the temperature of the universe dropped through 3000 degrees Kelvin at a time around 370,000 years after the Big Bang.
It would be good to know if we observe this flash of radiation in a nuclear fusion reactor as the plasma cools through 3000K. I understand that the temperature required for nuclear fusion is around 100 million degrees C so it should be possible to observe this effect as the plasma cools though 3000K. My expectation is that you will not see a flash of radiation at this temperature but it would be good to know for sure from someone working on nuclear fusion.
Richard
Relevant answer
Answer
Dear Prof. Richard Lewis,
Perfect, I hope you can investigate the old debate between Big Bang Theory and Stationary State Theory, with these new ideas and opportunities with ultra-fast cameras in Tokamaks.
Best Regards,
Prof. Wiltgen
  • asked a question related to Nuclear Fusion
Question
31 answers
To whom might be interested,
I have been thinking about prime numbers and how they might fit into our world, and this idea came to me that the primes might be constructed in a similar way to how elements fuse in stars.
To demonstrate my idea I wrote a short php script showing the construction of the first 25 primes. I have never seen anything like this before and I believe it is an original idea.
Would love to have some feedback on this from someone in number theory who have studied the primes.
Steven
.
Relevant answer
Answer
They orbit around some composite numbers like the electrons around the nucleo
  • asked a question related to Nuclear Fusion
Question
4 answers
There are PIDs but usually only the Proportional part of the PID algorithm is usually used
Mapping systems, as used in diesel engines
But make a several layer PIDs is difficult.
Map based systems (as example used in turbines or diesel engines) needs a lot of testing and works usually with new machines in controlled conditions
It would be better using an algorithm that adapt and slow increases or decreases control signal in order to obtain maximum performance.
Also some algorithm should advise of modifications out of expected values to advise about problems, making an efficient diagnosys of the system
I should need to use this kind of algorithm to control my simulations to reduce number of simulations but also to control my Miranda and Fusion Reactors
Perhaps some of the algorithms can be: Neural Networks, MultiLayer Perceptrons (MLP) and Radial Basis Function (RBF) networks. Also the new Support Vector Regression (SVR)
Relevant answer
Answer
I made an algorithm that theoretically reaches the end solution in the minimum time:
1. Set delta = (max-min)/2 for every parameter
2. The algorithm varied from center value to +1/2 delta and -1/2 delta one of the parameters and see which result is the best, then center that value to that
3. The same with all the parameter
4. Divide delta/2
5. Goto 2 until delta=minimum
The problem is that vary so much one parameter in one REAL machine it would be broken or stopped
Perhaps it is a better solution to go from the center, use delta=minimum delta, and going up multiply by 2 every time, then begin to divide again by 2 when entering in a second condition (to be defined)
  • asked a question related to Nuclear Fusion
Question
2 answers
if the output power is less than the propulsion input power, how nuclear fusion can be used in fusion space propulsion.
Relevant answer
Answer
We designed a fusion reactor that uses a plasma thruster to inject the plasma before compression. we calculated a propulsion force of 700 newtons.
Actually Pulsotron-3 recovers 88% of the electricity and can do the job:
  • asked a question related to Nuclear Fusion
Question
2 answers
In a Z-pinch test using Pulsotron-3 fusion reactor, I have seen at high-speed camera that a pyrex glass generated a beautiful green light during some milliseconds after the electromagnetic pulse was finished.
The magnetic field was over 300 kilotesla in the target that was several centimeters from the pyrex glass.
It can be seen under "Project log" here:
The pyrex glass was broken but I think there was not a high-temperature raise in the glass. What could generate the luminescence?
Relevant answer
Answer
Hola Javier,
Very intereasting observation. From our research on Xe excimer discharge lamps using a quartz or borosilicate glass vessel, we observe sometimes green luminescence, which we have attributed to the loss of Oxygen which goes hand in hand with the breakage of Si-O-Si bonds and thus subsequent Si2+ formation. These low valent Silica species cause defects in the glass structure and the vessel might be destroyed upon long term operation. Possible degraded glass can show luminescence due to either an [Ne]s2-[Ne]sp transition of Si2+ or other colour centers (low valent boron species).
You may find more information on the quartz /glass damage in the following paper, while I assume that pyrex (borosilicate glass) behave similar:
Green luminescence in silica glass: A possible indicator of subsurface fracture
Appl. Phys. Lett. 100, 114103 (2012); https://doi.org/10.1063/1.3693393
  • asked a question related to Nuclear Fusion
Question
3 answers
I have seen approximate formula depending on density and if it is fully or partially ionized.
I should add it to the excel table:
If there are several cases, I should like to add the cases to the excel table (I can use if inside excel formula), also visual basic can be used to include Bessel functions
Relevant answer
Answer
Dear Prof. Javier Luis López, interesting question. I found the following reference for general and discharges plasmas
also, I found instructive (for isotropic electron plasma in normal metals)
On the other hand, the most general equation comes in the case of an anomalous skin effect when Fermi surfaces are highly anisotropic. Please see:
  • asked a question related to Nuclear Fusion
Question
6 answers
Pulsotron-500K SE is open now until Jan31 to everyone that want participate in it!
The goal is to reach ignition by not heating electrons anymore in a nuclear fusion reactor.
Relevant answer
Answer
The log of the project can be seen by clicking in the folder "Project log"
Hello Amlaan, can you tell us your skills?. Do you participate or could participate in an R&D group?
  • asked a question related to Nuclear Fusion
Question
10 answers
I have read several papers about, but still I have not a clear idea. I have seen that as less density, higher plasma temperature and lower frequency the skin depth is higher. I think it can be calculated by reduce the frequency until the transmitted power is reduced due the electromagnetic field goes through the plasma
I need to calculate output ion current as a equilibrium plasma when affected by a current or voltage pulse.
Relevant answer
Answer
If you have a fully ionised plasma, the electron-neutral collision frequency will tend to zero (as you don't have any neutrals anymore) and the collisionless skin depth d should be taken: d = c/wpe
with c as the speed of light and wpe the electron plasma frequency.
  • asked a question related to Nuclear Fusion
Question
29 answers
In a fusion reactor, after fusions or transmutations, some ions scapes at high speed. If a positive ion is ejected and a magnetic field is generated, then electrons would goes exactly in the same direction generating and opposite field that would reduced to 0 the generated electric field. Fortunately in the P+11B fusion charges goes in the opposite directions to maintain a 0 kinetic momentum, then the field is 0 and electrons could be at the start of fusion, but also could go coupled to ions and not generate any EM field
Relevant answer
Answer
About TOF, there is an FFT using phase instead of frequency: https://www-leland.stanford.edu/group/Zarelab/publinks/686.pdf
  • asked a question related to Nuclear Fusion
Question
8 answers
Since each conversion process introduces more inefficiency during the production of electricity, wouldn't it be really beneficial to obtain the output of the fusion reaction particles as ionized atoms and use them directly to create a potential difference as if they are a power source?
Relevant answer
Answer
Yes.
Surround your fusing plasma with photovoltaic or Peltier-Seebeck elements - with suitably sized heatsinks on them.
Since your plasma is neutral, there's no flux of charge carriers that you can directly employ.
But the photons liberated from the plasma are admirably able to carry away heat.
  • asked a question related to Nuclear Fusion
Question
11 answers
Both England and China have drawing board plans for nuclear fusion power plants, which, everybody agrees, are absolutely safer than nuclear fission power plants, which produce 5% energy along with 95% radioactive waste.
Relevant answer
Answer
Current forecasts indicate that the primary energy consumption worldwide by 2050 will probably be doubled in comparison with the year 2000. The urgency of achieving zero-carbon power systems by 2050 dictates maximum achievable deployment rates of all renewable and other cost-competitive zero-carbon power sources. Johannes Schwemmer, director of Fusion for Energy, the European agency responsible for managing the ITER project said fusion power will not be industrialized and commercialized until at least 2060. At least until the middle of the century, I don't think we can talk about banning nuclear fission.
  • asked a question related to Nuclear Fusion
Question
11 answers
I am using a solver to reduce the simulations of Miranda fusion reactors, as long as it has a lot of input data and needs some seconds to simulate (I use C++ and 8 threads)
My idea is that the algorithm generates some input datasets, obtain results and using the results throw new datasets in the better conditions.
I am trying a genetic algorithm to automatize simulations but needs a lot of unuseful simulations to work.
I think a more sophisticated method that obtains a more useful datasets
I added the result of one of the datasets.
Relevant answer
Answer
At the end I had to use a genetic algorithm, but as long as I have to modify 5-6 variables I had to use the best between 1000 simulation results for next iterations to avoid lose a lot of possibilities. Using that I had to simulate >140000 reactors, after reactor number 20-30000 they did not reached ignition conditions. I am simulating about 10k-30k reactors every day.
Here is the result of one of them:
best regards
  • asked a question related to Nuclear Fusion
Question
3 answers
I am designing particle accelerators that sends protons again boron particles at 550keV. I calculated the deflection angle using electrostatics only and can have the deflection angle of 2 particles, but I would like to know the probability of every angle when colliding with a large number of particle targets.
Exist a program, table, web or paper that gives that result for an energy?
Relevant answer
Answer
I have read that the angle is similar to difraction probability and there are some ENDF files with test data
  • asked a question related to Nuclear Fusion
Question
1 answer
Fusion nuclear power, once again implemented, could be the most powerful source of energy for mankind. Although significant progress has been made in this direction, fusion facilities have not yet been implemented. Nuclear fusion power could not yet be done, but their season is rapidly approaching. The advantages of nuclear fusion energy are enormous.
Relevant answer
Answer
The current trend is to electrify the transportation industry. The nuclear fusion is a technology for producing electricity and has no direct connection with the transportation industry.
  • asked a question related to Nuclear Fusion
Question
9 answers
When nuclear fusion is controllable and energy is supplied indefinitely
Relevant answer
Answer
We are stil going to need water and to get rid of polluted water. If energy becomes very cheap there will be a change in which technologies are preferred for different treatment problems.
  • asked a question related to Nuclear Fusion
Question
3 answers
I where looking for elements that can absorpt neutrons without generating radioactive materials in order to be used in future Pulsotron reactor installations, and I found that most of them in earth are suitable. I found that could work:
C, O, Si, S, N, H
The most percentage of isotopes can receive one or two neutrons being stable, but if a neutron would be subtracted it would convert in an unstable isotope.
About that I was happy to know that silice, concrete and limestone could be used.
Relevant answer
Answer
interesting question
  • asked a question related to Nuclear Fusion
Question
17 answers
At the dawn, of the 21st century during a reign governed by money and greed the buzz in the economic and technological race was to build an economy based on hydrogen. A couple years later with the financial internet crisis of 2001 all this buzz disappeared and we entered a reign of terror and war governed by a different type of ethics…
Now, we are facing a different challenge: the climate change due to the over consumerism and accumulation of pollution since the 19th century. After decades of foolish hard geo-engineering experiments scientists, engineers and technologists have to come up with all kind of ineffective “solutions” (some are doing worse than good) to master the astronomical forces involved in order to control the effects of climate change and continue business as usual…
Hydrogen is seen as a non-polluting way to store renewable energies and nuclear energy since its recombination with oxygen produce only pure water. It is a transportable fuel for vehicles and other tools and devices running on electricity.
Further, some scientists fascinated by the solar nuclear energy (“illimited source of free energy”) have convinced uneducated deciders that the ultimate goal was to master the nuclear fusion and build an experimental international power plant called ITER.
Please, justify your position by sound arguments.
Thank you in advance for your esteemed expert contributions and for your understanding.
Kind regards.
No personal attacks, insults, pollution of the answers with popular press clippings from other discussion will be accepted.
Relevant answer
Answer
I agree with Dr. Dariusz Prokopowicz
  • asked a question related to Nuclear Fusion
Question
7 answers
Our fusion reactor Miranda have dozens of parameters to adjust to obtain reactions.
Our simulator uses an easy algorithm to simulate our models running 16 threads but it is difficult to change all the parameters so we have few data to feed the learning algorithm, so we need a neural network with a very fast method that learns with few samples.
Relevant answer
Answer
Use Extreme Leaning Machine, no iteration. One step learning.
Simple description available:
  • asked a question related to Nuclear Fusion
Question
9 answers
The problem is that the isolators parts of coils heat must be removed.
Isolation materials have low power transmission coefficient (about 0.6-2.5 W/mK) with respect copper (>400W/mK).
Unfortunately attaching directly copper parts to vacuum chamber wall would shortcircuit the internal coils
This problem was detected during the thermal design of Rita and Patricia fusion reactors
Relevant answer
Answer
Using water as a coolant one usually is able to prevent excessive heating of the coolant simply with adequate feeding. Limitations may arise from high dielectric constant of water and chemically induced electric conductivity of the water used. If those limitations are serious water can be replaced by transformer oil. But thermal properties of oil are nowhere near so good as that of water.
  • asked a question related to Nuclear Fusion
Question
1 answer
We should use it in calculus done on Pulsotron 500 machines
Relevant answer
Answer
I calculated at end 1.7MeV for alphas and 13.49Mev for the proton. The energy at proton is much higher due has lot less mass and inertia moment conservation
  • asked a question related to Nuclear Fusion
Question
3 answers
Dear RG colleagues,
Decay rate for tunneling through the barrier is calculated in many quantum text books. But, how can we proceed by reversing the situation where two approaching nuclei tunneling through mutual Coulomb barrier to come into nuclear force range to fuse together? Can we apply the scheme for calculation of the fusion cross-section for nuclear fusion reaction of the type d + d > 4He, using Gaussian type attractive nuclear potential along with Coulomb barrier?
Regards,
A Khan
Relevant answer
Answer
The problem to d+d>4He reaction is that the result nucleous should have the same momentum than the incoming nucleous, that is impossible if the result is one only
  • asked a question related to Nuclear Fusion
Question
1 answer
Nuclear fusion reactors live and die on how well they store their plasma in their reactor. All reactors to date have been unable to store their plasma for long enough at a hot enough temperature to reach net gain energy. For this project, we are attempting to use lasers to plug the holes in the plasma bottle, and recycle the energy into the reactor using a combination of fiberoptic cables, scintillators, and laser gain crystals.
The question is the following. What is the cheapest way of checking our confinement idea? We think a fuser might be the best option, but it has a grid in the way of the plasma causing lots of plasma leakage through conduction. But, if we could shield the grid properly using the lasers, we could demonstrate the plasma confinement principle.
What do you the community recommend? What do you think the most cost effective way of testing plasma confinement approaches are?
Relevant answer
Answer
Using a "-" cathode is enought to confine ions in a fusor, there are not any hole.
The main problem in the standard fusor is that you heat electrons that takes most of the energy and reduces ion density.
I would like modify a fusor to reach ignition but I should had to change a lot of things in it
In a fusor hot particles can be seen easily using a camera as long as they loses a lot of energy in a wide spectrum
Using 3 cameras you could make 3-d movies and use filters
I am designing a new sensor that calculates ion density and energy but not now as I am bussy building two fusion reactors
  • asked a question related to Nuclear Fusion
Question
2 answers
I need deviate a current of 400keV plasma.
If I use a perpendicular magnetic field I would deviate electrons to one side in a circular manner and ions in the opposite, I should like deviate them in the same direction.
The second problem is how not focalize them, because using magnetic lenses should focalize in different positions electrons and ions
Relevant answer
Answer
It is a good option using magnetic fields bacause they do not reduce the plasma speed. Our structure is a toroidal form that will have running plasma at 400-500keV and we want deviate about 45º, the problem is that the inducted magnetic field is very strong so we should use a energy pulse. Other system I cosidered is a perpendicular magnetic field that deviates the ions, electrons should make cirkes and should follow the ions. There are some other options.
  • asked a question related to Nuclear Fusion
Question
34 answers
In this idea, the future is assumed to contain super energy grids that provide huge clean amounts of electricity, and fuel. The energy production systems are to mutually supply a typical complete daily electrical load curve, and providing hydrogen-based fuels for relevant utilization.
An energy production unit consists of a fission/fusion nuclear reactor, and an accompanied water electrolysis system which receive its energy requirements from the reactor. Thermal energy, electrical energy, hydrogen, and hydrogen-based fuels are then available.
Due to their limited capability of handling highly variable loads, the base electrical load energy is supplied from the nuclear steam turbine generators while the mid-range and peak load sectors are supplied from hydrogen-based generators such as fuel cells, and internal combustion engine units. On the other hand, hydrogen fuel distribution systems will be used for supplying loads such as hydrogen fueled cars, and other thermal loads.
From a technological point of view, these systems can be practically realized. The nuclear energy is considered a clean source that can produce a massive amount of thermal energy. The energy conversion process is classically performed using the nuclear fission of the uranium; however, recently, stable nuclear fusion for energy production is practically available. With the recently discovered carbon-based filters for direct desalination of seawater, an unlimited source of freely accessible freshwater is possible.
In my opinion, such systems will secure the energy for the future with least environmental impacts; however, many studies are required for ensuring the success.
Your feedback and discussion(s) will be highly appreciated.
Best regards,
M. EL-Shimy
Relevant answer
Answer
Once the infrastructure for hydrogen-based electricity and hydrogen-based mobilty were present, then there would be no reason why the primary energy should not be generated be renewables alone. The main weakness of renewables is the storing of energy which would be resolved with a functioning hydrogen infrastructure. Hydrogen technology would enable non-central energy storage, a perfect couple with non-central energy production.
The main strength of nuclear is the base load capacity which is the more important the more the storage problem remains unsolved
  • asked a question related to Nuclear Fusion
Question
7 answers
Can we constructing a small system of heat generating fusion plant using tokamak magnetic confinement geometry, to produce a winding field in some ways similar to that in a modern stellarator, in the lab?
Relevant answer
Answer
I have seen with my own eyes (in an armoir of ENEA Centro Ricerche Energia - Frascati, Italy) the remains of THORELLO, a small toroidal chamber for magnetic confinement of plasmas, with radius not larger than 20 cm. It had been originally conceived for training on Langmuir probes. I guess Prof. Gabriele Chiodini, a particle physicist now at INFN and who is working on ATLAS, used to work with it - see e.g. Chiodini, G., C. Riccardi, and M. Fontanesi. "A 400 kHz, fast-sweep Langmuir probe for measuring plasma fluctuations." Review of scientific instruments 70.6 (1999): 2681-2688. .
  • asked a question related to Nuclear Fusion
Question
2 answers
EBC (Environmental Barrier Coating) may be used for the protection of graphite inside the nuclear reactor based on nuclear fusion. If it is true then, what type of EBC is used there. If the statement is not true then, why it (EBC) is not used there.
Relevant answer
Answer
Hi
Carbon components as graphite or CFC are no longer considered in Nuclear fusion due to their tendency to create hydrocarbons that may trap radiative tritium in large amounts. That's why only tungsten or its alloys is intended for the plasma facing components of ITER at present. Being a superconductor device, a cryostat surrounds the reactor. A concrete barrier is used for biological protection among other safety protocols...
Yours
F Tabares
  • asked a question related to Nuclear Fusion
Question
16 answers
The reactor based on fusion technology are the future power source. The use of magnetic field in stabilization of plasma under reactor core is quite challenging task. Please give me guidance to move forward toward the reactor technology by papers or book or valuable guidance or suggestions. For this i will be very grateful.
Relevant answer
Answer
Magnetic confinement fusion is an approach to generating thermonuclear fusion power that uses magnetic fields to confine the hot fusion fuel in the form of a plasma.
Articles:
Books:
Fusion: An Introduction to the Physics and Technology of Magnetic Confinement Fusion
By Weston Monroe Stacey, Wiley, 1991
Magnetic Confinement Fusion Driven Thermonuclear Energy
Bahman Zohuri
Springer International Publishing, 2017
  • asked a question related to Nuclear Fusion
Question
4 answers
Unlike tokamaks, field-reversed configurations (FRCs) for magnetic confinement of thermonuclear plasma are often thought to provide high betas, gas pressure to magnetic pressure ratio. But what experimental evidence is there for such claims?
Relevant answer
Answer
Dear Prof Kovalev,
it seems to me that the value of beta is not usually provided in FRC literature. Rather, the relevant quantity is s, the number of gyroradii between the null field point and the separatrix. Earlier reactor proof-of-concept studies focussed on values s > 20, but effective suppression of kink instabilities occurs at s --> 1. Another relevant quantity is the elongation: larger (smaller) values prevent tilting (reconnection) instability.
A notable exception is Ryzhkov, Sergei V. (2002). "Features of Formation, Confinement and Stability of the Field Reversed Configuration". Problems of Atomic Science and Technology. Plasma Physics. 7 (4): 73–75.
Table 1 of this paper displays values of experimentally measured, volume averaged beta between 0.75 and 0.95. 
  • asked a question related to Nuclear Fusion
Question
14 answers
We are using pure tungsten electrodes in a plasma focus device. While we thought we cleaned them well, with light abrasion, acetone and isopropyl, when we used them with a deuterium fill gas, the production of tungsten bronze and other evidence showed that we still had a lot of oxide left on. We must remove this before our next shots. I would also like to know if there is any way to be sure we have removed the oxide layer.
Relevant answer
Answer
 Hi Eric, are you able to comment on whether dissolving in 5% wt NH4OH at 80°C worked for you? I am in a very similar situation right now and looking for a good way to remove what I think is an oxide from tungsten. Thanks.
  • asked a question related to Nuclear Fusion
Question
9 answers
Can anybody provide me with a source for estimates about power output by fusion power? Can it be assumed that a fusion reactor has a power output in the range of some kilowatts? Thank you!
Relevant answer
Answer
Dear Volker,
first the health warning. Fusion power is 25 years away from being a reality, and it has been that way since the 1950's LOL.
Evidence from CERN and other research centres tends to show that fusion reactors are likely to be very big to generate more power than they consume, we are talking about 100MW or more.
Have a look at:
and the references given here:
Other small-scale work on things like cold fusion are mostly discredited:
even plasma injection systems are big.
as is ICF:
please mark up this answer if you find it useful
Best regards
Paul
  • asked a question related to Nuclear Fusion
Question
1 answer
We know that in a water-cooled system, like plasma facing component in an ITER-like fusion reactor, the maximum heat flux at the cooling tube should be lower than the critical heat flux (CHF) with an acceptable margin e.g. 1.4.
By modeling convective and conductive heat transfer for a plasma facing component we are able to calculate the maximum heat flux. But, what about the CHF, how can we calculate it and make sure that the good margin is available?
Relevant answer
Answer
CHF could be calculated with Tong-75 correlation ( original ref: Tong L.S., “A Phenomenological Study of Critical Heat Flux,” Proceedings of the American Institute of Chemical Engineers - American Society of Mechanical Engineers Heat Transfer Conference, San Francisco, California, ASME Paper 75-HT-68 (1975), but you can find it in several books and publications)
This correlation generally underestimates CHF. A modified version include a correction factor (>1) to take into account different tube configurations (smooth, swirl hypervapotron). For smooth tubes it provides a good estimation. For hypervapotron a correction factor up to 2 should be applied.
  • asked a question related to Nuclear Fusion
Question
2 answers
How do I measure shine-through and power desposition in the first wall of Tore Supra tokamak? What method did you use? 
Relevant answer
Answer
Do you mean the shine through of neutral beam injectors? You can use calorimetry or deduce it from the fueling rate of the NBI...
  • asked a question related to Nuclear Fusion
Question
9 answers
With the attachment linked to my question, I am looking for open references to the fluid dynamics of implosion towards nuclear fission. It seems that all literature is either proprietary or classified. My work is open to all, instead.
Relevant answer
Answer
Peter Sarnak, well-known number theorist from IAS sent my solution to Peter Konstantin, Princeton; Pfefferman, who wrote the problem definition for the NSE Millennium Prize; and Ya. Sinai, Princeton, who have not commented. My illustiruous  rivals include Terence Tao, UCLA, and Yau, Harvard. The latter are winners of the Fields Prize, so much smarter than me. But they are unaware that the divergence-free condition does not allow for the phenomenon of sound, too bad.
I admit to some level of frustration, but the rivalry between physicists and mathematicians is well-known. 
I practice constructive mathematics. A claimed solution must be exhibited. So far none from mathematicians. I am patient.
Thanks for your continued interest. Maybe we can meet when I return to Europe.
  • asked a question related to Nuclear Fusion
Question
13 answers
I would like to know that is there any other way to enhance the neuron flux level in a reactor without much change in the power level.
Like changing the mechanical design of fuel pin, fuel fraction, pellet design etc. to enhance the neutron flux level in research/test reactor without much change in the power level?
Relevant answer
Answer
The answer is yes. But it depends on what your goal is. If you're talking about increasing the neutron flux in a neutron beam that is exiting the core, or if you talking about increasing the neutron flux in the fuel, or in non-fuel regions.
To keep things simple, the fuel is a strong (neutron) absorber, but it also produces more neutrons than it absorbs. However, other regions of the core (poisoned coolant, control devices, etc) are strong absorbers without the production of neutrons.
So, in order to increase the flux in the non-fuel region, and keep the power constant, assuming a critical core, you would need to 1) reduce absorption in the non-fuel region, 2) counter that reduction in absorber in (1) by increased absorption in the fuel - to keep the core critical. This would shift the flux away from the fuel to non-fissionable materials, like the coolant and the moderator - keeping your power constant.
To increase the flux in the fuel without increasing power, you basically can't. Because any increase in thermal (slow) neutron flux (for BWRs, PWRs, and HWR) will cause an increase in thermal power output of the fuel. If you had a fast reactor, there will still be fast (neutron) fissions, thus increasing your thermal power - however, not by as much.
I hope this clears things up a bit, if you are looking for more specific answers, I would suggest reading the introductory chapters in any reactor physics text (i.e. Nuclear Reactor Physics - Stacey, Applied Reactor Physics - Hebert, etc).
  • asked a question related to Nuclear Fusion
Question
6 answers
At the quantum level I hypothesis that if we supercooled protons  and compressed two protons together they'd be able to overcome electrostatic repulsion and merge to combine as one. Then rapidly heat the combined protons, which would produce one of three occurrences. 1) 1 proton and 1 antiproton explosion, 2) The two protons stay merged and form a heavy proton, or 3) The two protons violently explode creating extreme temperatures.
Decreasing the protons to ~ 0K will decrease the strength of the nuclear moments allowing us to overcome part of the Coulomb Barrier decreasing the temperature needed for fusion.
Has this process been explored with nuclear fusion reactors?
Relevant answer
Answer
Hi,
interesting question. However I don't see how cooling could allow us to overcome part of the Coulomb Barrier - the electrostatic potential (as far as I know) is not dependent on the temperature. On the other hand, the tunneling propability of the two protons will exponentially converge to zero if the temperature is decreased to ~ 0 K, which makes fusion more and more unlikely.
  • asked a question related to Nuclear Fusion
Question
11 answers
I have to measure current due positive ions with respect negative ones but I can not use a magnetic field to measure them.
The system consist on a high density plasma thruster working over 50kV
Relevant answer
Answer
I have not yet gone through your calculations but I spotted that you set the diffraction grating line density to 2500/cm whereas one can buy 2400/mm. Spectral resolution to 6pm is achievable. What is more interesting than spectral resolution is how small a shift on a wide line one can resolve.  The technique I have seen used imaged the line onto the edge of a reflecting prism. This generated two signals that would be equal if the line centre is unshifted. The non equality then gives the line shift. Possibly this can be done on a solid state camera nowadays using software to fit line profiles and look for the shift.
  • asked a question related to Nuclear Fusion
Question
1 answer
I´m looking for an explanation for the fast direct reactions producing particles with discrete energies and the following compound reaction which results in a continuous neutron spectrum.
Relevant answer
Answer
As per my knowledge , the time remain same when we  will project a lighter particle on a heavy ion and also reverse process because in nuclear interaction every quantum number must be conserved. Time reversal symmetry is conserved in nuclear reaction that why time remain same for both. 
  • asked a question related to Nuclear Fusion
Question
7 answers
I was reading about the plasma-facing materials used in JET and ITER. I'm wondering why not a silica glass/graphite layered composite is used for that purpose, since amorphous silica is currently used as a radionuclide waste container (because of the flexibility of forming-reforming chemical bonds of its structure under radiation and the ability to accommodate any kind of ion) and graphite can dissipate heat so well. The proper alignment of the layers would permit heat dissipation with high efficiency. Why not?
Relevant answer
Answer
First you have do distinguish the plasma facing materials which are the materials which are in direct contact with the plasma and the blanket where the n - Li reaction has to take place to win new fuelling material. Such a blanket does not exist in JET which is basically operated with pure Deuterium only. Only few experiments with additional Tritium have been performed.
The PFC has to withstand an ion bombardment (sputtering, heat load), but also neutron impact (14.1MeV) and very high UV radiaton which can reach regions far remote from the plasma. On the other hand one has to keep in mind the impact of the PFCs on the plasma. If material is eroded it can enter the plasma and radiate which cools the plasma and can become a show stopper. this favors ligh elements like Be, C which can be fully ionized in the plasma and have moderate Z. Such materials can reach concentrations in the low % range without stopping a reactor. high-Z materails like W are more critical. Here the concentrations have to be below 10^-5 to allow for a burning plasma.
In fact for a very long time C was the choice for the PFCs in fusion experiments. It has a moderate Z, cheap, easy to machine and is very tolerant versus heat overloads since there is ablation only but no melting which causes droplets which can cause further melt events and impurities for the plasma. But low Z materials have in general a higher erosion rate by ion impact than high Z materials and C is even chemically reactive to hydrogen forming hydrocarbons. This lead to high erosion yields and the formation of hydrogen rich carbon flaces which puile up in remote areas in the vessel. In the view of a fusion reactor this means rich of radioactive Tritium. therefore, a C machine would in very, very short time hit the Tritium inventory limit. That was the final C show stopper.
A current trend are high Z-materials (tungsten) due to the low erosion yields. one just has to control the tungsten influx into the confined plasma (under investigation, e.g. ASDEX Upgrade) or multi-material PFCs where the main chamber wall are made from low-Z materials, only the divertor from tungsten. Here the ansatz is that melt damages of the first wall have less impact on the plasma and therefore more acceptable.
Beside the pure material properties one has to keep in mind thet high mechanical stresses occur in a tokamak (heating cycle).All components have also to be produced. The JET first wall also is chosen in the view of future experiments where the wall elements have to be actively cooled. There arise questions like how to integrate the cooling pipes into your PFC material. How to avoid stresses between the materials during the heating cycle (thermal expansion coefficient).
So, I am not an expert in amorph glasses, but I am not really sure if such considerations have already been made. A solution for JET only is falling short.
  • asked a question related to Nuclear Fusion
Question
11 answers
I want to find data on fusion reactions like the ones in carbon and oxygen buring processes (12C+12C, 16O+16O) but fusing the other isotopes of C and O. The same for nitrogen and fluorine, etc. 
Relevant answer
Answer
The currently best source for alpha- and proton-capture reaction (including (p,a) reactions) is in my view the compilation of Christian Iliadis and his group, see Nuclear Physics A 841 (2010) 1 (note this is a series of 4 articles in the same issue of NPA). On the 17O(p,a) reaction new results will come up soon, meanwhile you might want to look into Sergi et al., Phys. Rev. C 82, 032801(R) (2010), which is to my knowledge the most recent work.
Regarding 12C+12C (and likely the same for 16O+16O), this is much more difficult since the reaction is very complex, the experiment not easy and the mandatory extrapolation very uncertain, in particular down to astrophysical energies. To my knowledge astrophysicists very often still use Caughlan and Fowler, 1988, which is probably as good as any other source, if you keep in mind that the uncertainty is very large at astrophysical temperatures and probably heavily underestimated due to the problems mentioned above.
  • asked a question related to Nuclear Fusion
Question
15 answers
As can be seen in the attached picture, the toroidal coils produces a magnetic field parallel to the tokamak torus circular axis Bx. The poloidal coils produces vertical magnetic field By, then the composed magnetic field is drawn as Bxy.
Then theoretically the particles that goes parallel to the magnetic field escapes, so does the particles parallel to Bxy exits from the tokamak?
Relevant answer
Answer
Hello Javier,
If your system is simple as the one depicted, not taking in consideration electric fields but only the magnetic field, then in theory yes, the charged particles following the field lines would have a tendency to go out. Nevertheless there might be electric fields due to plasma currents that will (most probably) make the particle rotate poloidally, as well as curvature issues that you might want to take care of, then theory does predict the confinement of the particles (or at least of most of them). Several books (Chen, Bellan and Friedberg among others) do describe with detail the dynamics of charged particles in magnetic fields and they analyze toroidal configurations as well, you might want to take a look at one of those books.
Cheers
  • asked a question related to Nuclear Fusion
Question
3 answers
It is known that nuclear binding energy makes it energetically favorable for protons to undergo nuclear fusion forming heavier elements. This fusion now goes on in stars, and it only occurs at high pressure and temperature.
At an early stage of universe evolution, soon after the Big Bang, the universe was hot and dense. Why is it that not all protons did the nuclear fusion at that time? Why is there so much hydrogen left?
Relevant answer
Answer
Remember you need protons and neutrons to fuse. Now protons and neutrons are in nearly equal numbers in the early universe, and deuterium was created early on but it wasn't stable and easily broken apart from the thermal photons. It was not until later when the universe had cooled that nucleons could form stably, but in the intervening time a lot of neutrons had decayed into protons giving an imbalance of about 88% protons and 12% neutrons.
The universe then began to fuse into helium but the neutrons were quickly used up in the helium. By the time there was any significant amount of helium the universe was too cool to fuse the next step into carbon. This locked the universe into the ratios we see, about 92% hydrogen 8% helium and trace amounts of lithium  and others. That's still roughly the ratios we see today!
  • asked a question related to Nuclear Fusion
Question
8 answers
I would like to know what is the optimum magnetic profile in a plasma confined in a straight cylinder with magnetic mirrors. The main problem is that coils are separated too much is that the magnetic field in the center goes under 20T but I need 25T.
It may depend on the confinement time, plasma temperature and initial plasma density.
Relevant answer
Answer
Dear Javier,
The optimization depends on what you want to optimize. Lets assume that you want to optimize the extracted current ( or plasma density)  from the plasma device, then a parabolic profile (rising in the middle of the chamber) is the optimum. Whereas if you want optimize the confinement or looking for high charge states from the plasma device then a MIn-B configration is the best . But to acheive u need both radial and axial magnetic fields.
  • asked a question related to Nuclear Fusion
Question
5 answers
In the reaction D+Li6 it is obtained He4+22.5Mev or Li7 + H+4.5 or 3.5Mev.
What is the angular distribution of the output particles (He or H) with respect initial D direction?
Relevant answer
Answer
The only one source of information I can advice you it is JANIS. I followed this data base and found out information consider cross section for the mentioned reaction and angular distributions of its product. There was also information regarding the references. If you need any detailed information regarding JANIS and its use just let me know.
with regards
Slawomir
  • asked a question related to Nuclear Fusion
Question
11 answers
I should need the tables in barns or similar with respect incident energy between 0.3 to 3 MeV range in order to help in calculus.
Relevant answer
Answer
Is it what you need?
Actually there are the global optical potetnials fitting the elastic scattering data very well. They have some limitations on the target mass and energies, but one may use it for estimations at least... However in this case you have to apply special computer codes in order to solve the nucleus-nucleus scattering problem.
  • asked a question related to Nuclear Fusion
Question
2 answers
It is needed to increase Pulsotron efficiency about 10-20%. One way could be add muons.
I have read that muon fusion is not feasible due it is needed more energy than released as long as it is needed 150-500MeV to generate them but some of them escapes with alphas.
As long as I can compress plasma using Pulsotrons, I could add a third tube to generate muons.
Would be useful to compress p+D plasma and adding muons to obtain more MeV than injected?
Relevant answer
Answer
Apparently,muons injected right away according to your proposal could catalyse some fusion processes which quantitatively are strongly temperarture and density dependent.However,the experiments would remain at a 'Toy' level remaining from the energy breakeven bull-park.
  • asked a question related to Nuclear Fusion
Question
11 answers
We know following reactions:
D+D = T + p
and
D+D = He3 + n
Why not: D+D=He4 + nothing?
Relevant answer
Answer
My answer is generalized for all fusion of any two isotopes.
Most fusion events have the same number of particles on the left and right hand side of the state equation.  Most fusion events of two particles produce a fusion, followed by a fission into two particles.   I know of no theory that predicts particle conservation, just it's been experimentally determined.  I've been reading up on "atomic collisions," which  you might search more on using those keywords.
A short answer is conservation of momentum.  The two particles total momentum on both sides of the state equation must be conserved.  Thus, if two particles hit, two particles must depart, at appropriate angles and energy.  The exception is the truly head on collision, where just one particle can conserve momentum.  But what is 'head' on for two bags of quarks?
Looking at the details, two nuclei collide in one of several ways. Direct head on is rare, and the quarks intermingle, forming a single nuclei, that might not fission, but most often does, for most all isotopes, as established by experiment.  A glancing blow, where the two nuclei 'touch' each other, results in immediate fusion, and attempts by the nucleons/quarks to establish the 'lowest' possible energy ground state, means something must be ejected, to release the kinetic energy from the two nuclei's velocities, that resulted in collision.  This release can be in the form of radiation, but is most often a particle, like neutron, proton, a pair of such, commonly an alpha particle, or a fragment that is larger.
Why a particle over radiation?  Some say the particle contains more energy than radiation and that's how it gets decided.  If the excited state is too high, then a particle with excess velocity is ejected.  If the excited state energy is low enough, then radiation might result.  But I have not read this is a 'rule', just conjecture, and is not followed for all isotopes.
Another way is for two particles to approach each other, and one fragments, where in the case of D+D, the only fragments possible are n and p.  And one of those fragments can fuse with the unfragmented D.
What actually happens?  You would have to look at the quarks and QED and such, and establish 'ratios' of results based upon angle of collision and point of intersection.  I wonder if anyone has done that.  And for what elements.  Janis and Empire supply some collisions, but only based on database queries, so one would have to look at their referenced sources, for both theoretical and experiment results. 
  • asked a question related to Nuclear Fusion
Question
33 answers
It would be very interesting and important to get an answer within the quantum mechanics approach because nuclear fusion occurs anywhere (in Universe, in Tokamak, in an explosion of the little hydrogen sphere by the laser impulse ) where there are the moving with high velocity and high density of the charged particles which produce the high magnetic field each for another and interact each another by these strong magnetic and electric fields. I can not understand , why do the quantum people take into consideration the electric fields and absolutely neglect these strong magnetic fields ? 
Is the role of these strong magnetic fields between nuclei, in fusion process, negligibly small ? 
Relevant answer
Answer
They do not neglect.
See Acc. Chem. Res. 47, 417-426 (2014) and references therein
  • asked a question related to Nuclear Fusion
Question
8 answers
The switch must deliver the energy stored in 50kV capacitors. I would place some of them in parallel to obtain 0.5-2 Megaamps.
We could use a trigatron but I do not know if it would work well with AC current. 
I could not use power mosfet or SCRs unless place them serially.
Other option is using a mechanical switch, but it would be almost impossible to switch in so short time.
We need also a trigger generator with more than 12 outputs that generates independent triggers within 1ns accuracy.
Relevant answer
Answer
Plasma physicists in Dense Plasma Focus research cope with a similar problem: capacitor banks (ranges are 20 - 45 kV, 1 kJ - 1 MJ) should feed a plasma (100 kA - 1 MA) in less than 2 - 3 microseconds. Usually, they use no trigatron. Rather, they connect the capacitor bsank and the electrodes with a spark gap and a series of low-inductiance conductors. Total inductance should never exceed 10 nH: this is a severe requirement indeed, and suitably sphaped conductors are to be used. See Heinz Knoepfel's comprehensive treatise, "Pulsed high magnetic fields: physical effects and generation". 
  • asked a question related to Nuclear Fusion
Question
4 answers
D+D reaction generates 14MeV neutrons that scapes from the reactor loosing its energy that could perform more useful chain reactions. The neutrons damages also the reactor container and generates radioactive isotopes increasing the operation cost.
Using a high pressure perhaps the cross section of D would be enought to capture neutrons to generate tritium that would react inmediatly whith other deuteriums.
The reactor size is between 10um and 2mm.
This study would will be useful in the design and operation of the Pulsotron-3 fusion testing device.
Relevant answer
Answer
I don't think that just rising the pressure will be sufficient - those 14 MeV neutrons have a very small cross section even with solids (lead for example does not shield neutrons effectively even with its high density).
Cadmium or Boron are good absorbers for neutrons but only for slow ones (so some 100 meV at most).
  • asked a question related to Nuclear Fusion
Question
3 answers
Is the resonance absorption more important than the collisional absorption?
Relevant answer
Answer
Thanks a lot Prof. Vita and  Prof. Sheikhdom-Sabzevari for your responses,  I am researching about what factors can increase the absorption in laser fusion.
  • asked a question related to Nuclear Fusion
Question
11 answers
Recently unprecedented high power capacitors were built and tested. A capacitor can deliver more than 10 mega amp to a test sample. The resonance frequency goes over 2 gigahertz and can be increased.
The question is now, if such capacitor can help scientists or the general public with high power electronics, high power laser, fracking, rail gun design, particle accelerators, or has any other uses.
Relevant answer
Answer
It would be extreemely interesting to check the operation of such capacitors in fast discharge circuits for the production of plasma shock waves.
  • asked a question related to Nuclear Fusion
Question
4 answers
Nuclear fusion potential
Why the electron cloud is not considered in the calculation of nuclear potential? And, only protons are contributed in the Coulomb term of nuclear fusion potential?
Relevant answer
Answer
Hello!
For interpreting nuclear fusion measurements at stellar energies (deep sub-Coulomb energies) the electron screening effects on the Coulomb potential between the colliding nuclei are critical. These effects can change the fusion probability by orders of magnitude. Understanding and quantifying such effects are a long-standing issue in nuclear astrophysics. However, as the collision energy increases, these effects become smaller as the energy scale of the electrons (e.g, keV) turns to be much smaller than the radial kinetic energy (e.g, MeV) of the fusing nuclei.
Cheers,
Alexis
  • asked a question related to Nuclear Fusion
Question
6 answers
We can obtain the fusion rate by using cross section, ion density, and speed. The cross section is calculated using particle accelerators.
Heating to 25keV plasma is not the same than throwing ions again a blanket because when heating a plasma, not all the energy is used to accelerate ions again ions but also to make rotations and elastic/non elastic shocks. But when heating the shock rate is increased.
My doubt is at the same ion energy level (as example 25keV) what is really the heating efficiency with respect using linear accelerators.
Relevant answer
Answer
I am interested in the similar study by using particle accelerators. 25keV ions can be obtained easily by DC-acceleration and the efficiency is high, but the motion is directional. Superimposing of 12.5 keV rf modulation on 25keV-DC, Ei = 12.5 ~ 37.5 keV, is possible to make similar motion to thermal random motion used in nuclear fusion reactors. But the efficiency becomes down to several %, and the value becomes lower especially for large-current/power ions. D-D, D-T collisions can be induced by using two or more accelerators, but the efficiency is very low due to only one reaction at one beam-beam collision, in comparison with multi events to induce reaction for random motion in nuclear fusion reactors.
  • asked a question related to Nuclear Fusion
Question
4 answers
In inertial confinement fusion, ion beams have a initial velocity when they collide on the target . How can I calculate the velocity of layers later? Could you please introduce a reference for it to understand how to calculate it .
Relevant answer
Answer
Thanks a lot. Is it is very good . I want to use from results. Is it same for heavy ion beam?
Best Regards!
  • asked a question related to Nuclear Fusion
Question
11 answers
In non-thermal Plasma the electrons are at temperature much higher than the heavy ions temperature (usually room temp.) If we provide a plasma system in the laboratory like the earth magnetosphere how can we rise the temperature of ions in this situation?
Relevant answer
Answer
Thanks Johannes, Cyclotron radiation is very low if the plasma ions moves well below relativistics speed (a few keV), gamma is about 1, it does not means that elevated by 4th power. I think you should refer to Bremsstrahlung thermal emissions.
I think (I have not data about ion emissions, as usually it is said to be much lower than electron ones) that Bremsstrahlung depend on square of acceleration, that must depends on square of speed. But as example a Deuterium plasma with mass 3600 times higher than the electron the "plasma-with-heated-ion-only" emissions should be 1/3600 of the thermal equilibrium plasmas. If true it is a very good notice for fusion, because Bremsstrahlung seems to depends linearly with energy
Stefan Boltzmann is an experimental equation used for plasma in equilibrium, dominated mainly by electron emission.
What other radiation must us to considerer in ion only heated plasmas?
  • asked a question related to Nuclear Fusion
Question
36 answers
For years, scientists have assumed that the sun is an enormous mass of hydrogen. Galileo was the first to propose that the sun is filled with gas. But Dr. Oliver Manuel says iron, not hydrogen, is the sun's most abundant element. IF his suggestion is true then it may imply that the source of solar energy is different of the presently held theory of hydrogen fusion.
In principle, Dr. Manuel suggests that the hydrogen-filled sun hypothesis is obsolete. See: http://arxiv.org/ftp/astro-ph/papers/0410/0410569.pdf
Reference to Dr. Oliver Manuel's papers:
”An iron-rich Sun and its source of energy," Proceedings of the 8th International Symposium on Nuclei in the Cosmos, Vancouver, BC, Canada, 19-23 July 2004 (Manuscript submitted for publication) http://www.omatumr.com/abstracts2005/IronRichSun.pdf
Others:
1. “Xenon in carbonaceous chondrites”, Nature 240, 99-101 (1972)
2. “Strange xenon, extinct super-heavy elements, and the solar neutrino puzzle”, Science 195, 208-210 (1977) http://www.omatumr.com/archive/StrangeXenon.pdf
3. “Solar abundances of the elements," Meteoritics 18, 209-222 (1983);
4. “The Sun’s origin, composition and source of energy”, Abstract 1041 , 32nd Lunar and Planetary Science Conf., Houston, TX, March 12-16, 2001, LPI Contribution 1080 (2001).
5. “Composition of the solar interior: Information from isotope ratios," Proceedings of SOHO 12/GONG Conference on Local and Global Helioseismology: The Present and the Future, 27 Oct-1 Nov 2002, Big Bear Lake, CA, U.S.A. (ESA SP-517, editor: Huguette Lacoste) pp. 345-348 (2003): http://www.omatumr.com/abstracts/gong-2002.pdf
6. A Journey to the Core of the Sun: Chapter 2 - Acceptance of Reality (Jan 2014)
So do you agree with Dr. Manuel's suggestion of iron rich sun? Your comments are welcome.
Relevant answer
Answer
So, there are several Fe lines in the range of 171 Angstrom, the problem is that if you use a filter in that range - these lines are blocked (also basic optics).
Furthermore it doesn't matter wether you look at the emission or absorption lines as they are identical...
So, if you cannot really disprove my simple arguments, I see no more value in discussing such a matter any further...
  • asked a question related to Nuclear Fusion
Question
3 answers
I was always interested in laser fusion, however, I have very little knowledge in the underlying physics of the plasma ignition, which I understand is the main source of the problem. The recent breakthrough however rekindled my interest and hence the question. Physically, what is the source of the problem? Is ignition the main problem or is it the manner of fuel addition after ignition? Is it a technical challenge or is there some lack of understanding of the governing physics?
Relevant answer
Answer
The physical problem is that it is very difficult to drive the fuel capsule into a state where the energy produced by fusion exceeds the losses due to,for example, radiation. In the simplest case these conditions are described by the famous Lawson criteria, which for inertial fusion says that capsule must achieve a minimum temperature and areal density, in order to produce and then trap fusion alphas and bootstrap to ignition. There are several potential reasons why current experiments fail to reach these conditions. The recent experiments were designed to control one of the possible causes, the growth of Rayleigh-Taylor instabilities in the core of the capsule, which potentially injects cold material into the core, cooling it down. Fusion capsules are unstable to this and so it's an important effect to understand: the recent results have shown that by using designs that reduce RT growth capsules can get closer to ignition than ever before.
  • asked a question related to Nuclear Fusion
Question
10 answers
50 years of research and development has not led to any conclusive direction.
Relevant answer
Answer
First of all: are we talking about inertial confinement fusion (ICF) or about fusion energy in general?
If we just talk about ICF, I would say it is not very practical for energy production, because the technical processes involved are quite complicated, first of all the refuelling is troublesome (but that doesn't mean that we can learn a lot of fundamental science from it).
If we talk about fusion in general there are several issues to be adressed:
1) Just because it is no easy task, we should stop try to achieve it? - that sounds not like a thing a ambitioned scientist or engineer would say (keep in mind that fusion is the most efficient method of energy production which nature hase to offer, as far as we know).
2) @ S. V. G. Menon: The worldwide yearly budget that is spent for R & D of fusion technology is neglible compared to the fundings for solar, wind, etc... Thus your argument is not really valid (in fact the energy production should be a mixture of all possible ways which are non-polluting).
3) @ Henk Smid: An observed net power output is also quite remarkable given the fact that the fusion reactors that we have now are not optimized for power output - they are all scientific reactors which means that they are for studying the scientific concepts of fusion and not for producint power. The first reactor which is supposed to deliver more power than it consumes is the ITER reactor - currently built in France.
The most promising fusion concepts are the TOKAMAK and the stellerator, but to my personal opinion it could be also a hybrid of those two which will make fusion available for the common energy markets.
  • asked a question related to Nuclear Fusion
Question
1 answer
I need to find papers where fusion is investigated within a quantum mechanics approach and 
exactly in a strong magnetic field, with quantitative results.
Can magnetic field be of primary importance for fusion process?
Relevant answer
Answer
I take it you'd need to describe the whole fusion process? which involves many particles, some of which will take part in the end to end fusion process itself, but most will inevitably not.
Charles Joachain's "Quantum Collision Theory" gives the appropriate background, as does parts of Fetter & Walecka's "Quantum Theory of Many Particle Systems"
  • asked a question related to Nuclear Fusion
Question
6 answers
Can anyone help me in find energy values required for the nuclear fusion of some light elements of the periodic table, example: N+N -> CO?
Relevant answer
Answer
Any nuclear chemistry or nuclear physics text will help you with this. N+N has a mass of 14.00307+14.00307 mass units. Going to C+O (ignoring minor chemical bond energies) gives a final mass of 12 + 15.99491 mass units. The reactants are 0.01123 mass units heavier. From E=mc^2 this is identical to an energy release that works out to be 10.5 million eV. There is an electrostatic barrier keeping two Ns apart that is roughly equal to a 12 MeV input requirement (corresponding to a temperature of about 140 billion kelvin). Isotopic masses can be found on-line at a variety of sources.
  • asked a question related to Nuclear Fusion
Question
1 answer
Either a preprint or a full recent paper link or title would be useful.
Relevant answer
Answer
Your question is rather general. What specific dynamics are you interested in? MHD effects? Applied to stars? Tokamaks? Below a few articles that might be of interest, related to the development of ITER:
  • asked a question related to Nuclear Fusion
Question
3 answers
In tokamak, the bootstrap current is an additional toroidal current driven self-sufficiently by frictional momentum balance between trapped and passing particles due to neo-classical effect i.e. toroidal geometry. The magnitude and shape of the bootstrap current is largely determined by magnitude and profile of pressure & density, of course subject to collisionality condition satisfied. That is plasma needs to be in collisionless regime for significant bootstrap current. Since plasma pressure gradient is highest towards edge, bootstrap current is also large in peripheral region and minimum or zero at the center. Does this profile of current resembles to a Bootstrap? Why it is named so?
Relevant answer
Answer
As far as I am aware, the expressions for the bootstrap current were calculated in papers by Galeev and Sagdeev, JETP Letters, v13 , p 162 1971 (page number of the Russian version) and even earlier in Soviet Phys JETP v 26, p 233 , 1968 (translated version).
The term Bootstrap perhaps was first introduced by R. J. BICKERTON , J. W. CONNOR & J. B. TAYLOR , Nature physical science 229, 110-112 (25 January 1971) | doi:10.1038/physci229110a0 who have discussed a possibility of stationary tokamak, which is self -supporting itself via enhanced radial diffusion due to the noted above friction between the trapped and passing particles. Similar ideas were proposed also by Kadomtsev and Shafranov, IEAE paper of 1971, p 471. The term "Bootstrap" is used here to mean self-supporting (http://en.wikipedia.org/wiki/Bootstrapping), it is not related to any features in the current profile.