Why people are so optimistical to Polywell?

[Joseph Chikva]

Beam emittance is where streams of mono-energetic ions tend to diverge because there is no magnetic effect between ions moving at the same speed so their space-charge causes electrostatic repulsion within the beam.

Mr. Half-educated, the repulsion forces of space charge are weaken as square of relativistic (Lorenz) factor. So, if you have electron beam with factor equal to 10 that correspondents to KE of about 5 MeV, repulsive forces in our frame of reference will be weaken 100 fold.
And even a small amount of ions (here I do not talk aboution beam - only cloud) can dramatically compress that beam in radial direction.

Do you have a link for an article on that? I had never heard that one before.

I have not link. But will search. I thought that it is well-known fact.

[MSimon]

I'm strictly a semi-professional when it comes to physics. I use it in my work when it comes up but the only formal training I have (other than high school) was the US Navy Nuke Power School. But I have been a very interested amateur all my life.

I never heard of this:

the repulsion forces of space charge are weaken as square of relativistic (Lorenz) factor.

[Joseph Chikva]

Do you have a link for an article on that?

Here is a quote that we talk about:

...the repulsive forces between the moving electrons are reduced by a factor that is very, very slightly less than one: ie by (1/γ2).

This is a link from which I quoted: http://www.phys.unsw.edu.au/einsteinlig ... e2_FEB.htm

[MSimon]

Do you have a link for an article on that?

Here is a quote that we talk about:

...the repulsive forces between the moving electrons are reduced by a factor that is very, very slightly less than one: ie by (1/γ2).

This is a link from which I quoted: http://www.phys.unsw.edu.au/einsteinlig ... e2_FEB.htm

Thanks!

[Joseph Chikva]

Thank you too.

[Joseph Chikva]

Beam emittance is where streams of mono-energetic ions tend to diverge because there is no magnetic effect between ions moving at the same speed so their space-charge causes electrostatic repulsion within the beam.

I have just now noticed what you mean talking about beam emittance. Beams can be considered as mono-energetic only for very raw estimations.
One more time you are wrong.
As using term of emittance we deal not only with coordinates but with phase volume.
So, speaking on more clear for you language it is necessary to say on both: about geometric divergence of beam, and also about its temperature as well. Because that I spoke about cooling mechanism considering emittance.
Though unfortunately I don't have a big hope that you will understand that.

[chrismb]

I'm strictly a semi-professional when it comes to physics. I use it in my work when it comes up but the only formal training I have (other than high school) was the US Navy Nuke Power School. But I have been a very interested amateur all my life.

I never heard of this:

the repulsion forces of space charge are weaken as square of relativistic (Lorenz) factor.

MS, this is correct but you probably know this already as a natural consequence of magnetism.

This (and the link) are showing that if you have two charges moving relative to each other then the electrostatic forces they feel between each other is less than if they were stationary. Instead, there is a magnetic field produced in each other's frame.

Any 'observing' charge at a relative velocity somewhere between both will feel a magnetic field from both and a reduced electric field from both.

Any 'observing' charge at a relative velocity the same as one of those particles will feel no magnetic field from the one it is travelling with, but a 'full' electric field from it.

You, actually, know this already even if you don't realise it because it is the explanation for electro-magnets. Get the electrons moving in the wire and their 'electrostatic' field becomes a 'magnetic' one in your inertial frame.

In JC's confabulation, the fusible ions would not be going quick enough for their 'space charge fields' to barely change. But he also has relativistic electrons running in the opposite direction. As a result, it is the electrostatic fields of the electrons that diminuishes to next to nothing (as far as the ions experience it) and instead they produce a magnetic field that the ions experience. In the meantime, the ions are then not space-charge neutralised, due to this effect, and so they will undergo emittance growth.

A thermal plasma has ions and electrons zooming in every which direction, so all such effects add and subtract to no overall effect. It is only when an additional differential particle current is induced in the plasma that there is any pinch, because then there is an uneven population of plasma particles that are going in the opposite direction to that current at any one time, so they experience a magnetic effect.

This is what I have been trying to explain to Mr. Forget-quantum-tunelling, but with no success whatsoever.

[chrismb]

A neuro-typical earthling friend of mine explained to me yesterday that many neuro-typical earthlings hold ideas and opinions formed on an irrational basis, and that because their starting position is an irrational one then is impossible to use rational logic to move them from that position.

Therefore, recognising that this is the case here, I hereby desist in this thread.

[Joseph Chikva]

A neuro-typical earthling friend of mine explained to me yesterday that many neuro-typical earthlings hold ideas and opinions formed on an irrational basis, and that because their starting position is an irrational one then is impossible to use rational logic to move them from that position.

Therefore, recognising that this is the case here, I hereby desist in this thread.

Good luck.

[Joseph Chikva]

I have a question but our "expert" has escaped having left me in ignorance.

the repulsion forces of space charge are weaken as square of relativistic (Lorenz) factor.

MS, this is correct but you probably know this already as a natural consequence of magnetism.

Any 'observing' charge at a relative velocity the same as one of those particles will feel no magnetic field from the one it is travelling with, but a 'full' electric field from it.

Can anybody explain me if the first claim is correct and repulsive force is weaker for the stream of particles also having no the relative speed between each other why

charge at a relative velocity the same as one of those particles will feel no magnetic field?

And what meant with feel no magnetic field?
May be that is only the same electric field the strength of which perceived differently depending on the frame of reference?

I gave him as I thought clear even for him explanation why pinch-effect is possible. May be I said something irrational.

[MSimon]

This (and the link) are showing that if you have two charges moving relative to each other then the electrostatic forces they feel between each other is less than if they were stationary. Instead, there is a magnetic field produced in each other's frame.

I knew that. I probably misread the explanation or I would have gotten that. Let me go back and look at the "conditions" again. I'd like to figure out why I didn't see that the first time I read it.