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Stanley514
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Is it possible to use neutral beam accelerators to smash deuterium atoms at each other to achieve practical fusion?
In this experiment they mention ion beams.If they use ions, then I do not see how could they get away from space-charge problems and similar.I meant rather to use neutral beam.This was actually one of the first fusion experiment. The latest attempt was SIGFE at the University of Wisconsin, Madison.
If you ionize your neutral atoms for acceleration then what you get is an ion beam.Stanley514 said:In this experiment they mention ion beams.
...
We could slightly ionize deuterium vapour just to make it conductive.And after speed it up with help of electrostatic accelerator.
Is it really necessary to ionize each atom?How then reilgunIf you don't ionize them then they don't accelerate...
Stanley514 said:Is it really necessary to ionize each atom?How then reilgun
works without any ionization?Maybe small ionization is sufficient?
What would you say about electrohydrodynamic generator http://en.wikipedia.org/wiki/ElectrohydrodynamicsIn which electrically charged particles used to flow and generate electricity?It is not necessary to ionize all the atoms or molecules in it.Creating some small charge is quite sufficient.Do you think it wouldn`t work in reverse?Principally we could use electromagnets too.But in this case we whould need to pare deuterium with something magnetic.Maybe some Iron hydride molecules.Instead you have to use electric charge to accelerate them, which requires ionization of the atom, otherwise it is neutral and won't be accelerated.
Stanley514 said:What would you say about electrohydrodynamic generator http://en.wikipedia.org/wiki/ElectrohydrodynamicsIn which electrically charged particles used to flow and generate electricity?It is not necessary to ionize all the atoms or molecules in it.Creating some small charge is quite sufficient.Do you think it wouldn`t work in reverse?Principally we could use electromagnets too.But in this case we whould need to pare deuterium with something magnetic.Maybe some Iron hydride molecules.
There already exist some storage rings which designed for neutral atoms.
http://accessscience.com/content/Neutral-atom-storage-ring/YB050460
I guess if it could be stored then it could be accelerated too.
If you add an extra electron to the hydrogen atom, you have a negatively charged atom. You can accelerate this, and if you then strip off the second electron with a very thin foil, you will have a neutral beam.Rive said:If you ionize your neutral atoms for acceleration then what you get is an ion beam.
If you don't ionize them then they don't accelerate...
Unfortunatly it will create the same space-charge problems as in case with positive ions.Problem with beam density.To get it really dense it should be constantly almost neutral.I guess.If you add an extra electron to the hydrogen atom, you have a negatively charged atom. You can accelerate this, and if you then strip off the second electron with a very thin foil, you will have a neutral beam.
Stanley514 said:What do you think the most perspective direction in fusion power research up to date?
Something that is cheap to implement and quite simple?
Do you think Polywell could be treated seriously?The closest thing in my opinion is the Polywell WB-6 device.
Stanley514 said:Do you think Polywell could be treated seriously?
And why it going to be cheap?As I know it would still require to have superconducting magnets to create strong enough magnetic field.And vacuum.So why is it going to be cheap?
Stanley514 said:Why Polywell is going to be cheaper than Tokamak?
Stanley514 said:Why Polywell is going to be cheaper than Tokamak?
Tests made on a large variety of machines, over a wide range
of drive and operating parameters have shown that the loss
power scales as the square of the drive voltage, the square
root of the surface electron density and inversely as the 3/4
power of the B fields. At the desirable beta = one condition,
this reduces to power loss scaling as the 3/2 power of the
drive voltage, the 1/4 power of the B field, and the square of
the system size (radius). Since the fusion power scales as
the cube of the size, the fourth power of the B field, and a
power of the E drive energy equal to the E-dependence of
the fusion cross-section (cross-section proportional to E to
the s power), minus 3/2. For DD, s = 2-4, while for DT, s =
3-6 in useful ranges of drive energy. For pB11, the cross
section scales about as s = 3-4 over the system-useful range.
Thus, the ratio of MG power loss to fusion power production
will always decrease with increasing drive voltage,
increasing B field, and increasing size. ... This is not the case in Maxwellian,
equilibrium fusion devices...
Stanley514 said:Could somebody calculate how dense should be deuterium ion beams that directing them at each other would produce some net energy?
Electrons are ubiquitous and easily accelerated to say 100 keV. Building ion sources of deuterium or tritium is very difficult. Accelerating these ions to 100 keV while controlling the defocusing space charge forces is extremely challenging.beatlemaniacj said:The Farnsworth Fusor is an example of this. It takes 2-4 linacs (basically TV tubes with the fronts taken off) And accelerates them to high energies into a small, spherical, metal, "cage" that is electrically charged and fuses them to produce helium3 and a steady supply of neutrons. I am currently making one with the help of a physicist. Obviously the theory of operation is much more complex than this, but that is just an overview.
Stanley514 said:Could it be made that simple?
Stanley514 said:Could they ever become practical working on D-D fuel?
Stanley514 said:Why DPF produces lots of X-ray?Is there no such problem with other types of fusion?
I don't think that claim has validity without public release of the WB-6 results.Drakkith said:The Polywell is a new concept that hasn't had 30+ years of development behind it, so it might be a little to early to really say either way. The WB-6 showed very good results. ...
For a colinear beam, sure, but that is not the case for one of these fusors as the poster has in mind, which are essentially anode - cathode tubes. Add D or T gas with a high E field and it is quickly ionized. They appear to quite simple to construct.Bob S said:Electrons are ubiquitous and easily accelerated to say 100 keV. Building ion sources of deuterium or tritium is very difficult. Accelerating these ions to 100 keV while controlling the defocusing space charge forces is extremely challenging.
The problem is a 'bounce' off collision is much more likely than a fusion event, regardless of density, so that beam-beam attempts inevitably waste more energy than they can generate.Stanley514 said:I read claims in a scientific magazine that if you direct D and T beams straight at each other and make them collide, then if their density will be higher then 10^14 ions per cm^-3, then fusion will become practical and give some surplus energy.To achieve such ion densities you need ion beams with current over few tens of Ampers.They also claim that modern high-current ion drivers allow to achieve currents over 1 million of Ampers.With energy of ions over 1 MeV.Could it be made that simple?
mheslep said:I don't think that claim has validity without public release of the WB-6 results.
I fairly sure I recall that the results were *not* released, though there has been a lot of informal inference to read about based on some continued funding.Drakkith said:I think I remember reading the results, but I don't have the link anymore.