Why people are so optimistical to Polywell?

[KitemanSA]

Why you call moving mono-energetic plasma "HOT" and not "HEAVY"?

Tokamaks use HOT Maxwellian plasmas to get a small part of the ions hot enough (high enough energy) to fuse. Polywell is intended to have ALL the ions at that high energy. All ions will be DARNED hot, moo-energetically at the high end of what would be the Tokamak energy distribution. In my discussions here, HOT equals hign energy, not necessarily Maxwellian. Thermalization is then the process of making things more Maxwellian.

[Joseph Chikva]

Why you call moving mono-energetic plasma "HOT" and not "HEAVY"?

Tokamaks use HOT Maxwellian plasmas to get a small part of the ions hot enough (high enough energy) to fuse. Polywell is intended to have ALL the ions at that high energy. All ions will be DARNED hot, moo-energetically at the high end of what would be the Tokamak energy distribution. In my discussions here, HOT equals hign energy, not necessarily Maxwellian. Thermalization is then the process of making things more Maxwellian.

Thanks, I have already understood that you (and not only) use the new definitions differring from conventional.
And also have a naive idea that plasma in Polywell will be cold or not-thermalized (by your definition). But that is not truth.

[KitemanSA]

And also have a naive idea that plasma in Polywell will be cold or not-thermalized (by your definition). But that is not truth.

We shall see. That is what experiments are for!

[ladajo]

Yup. The whole point.

Regardless of predictions, Polywell is a little studied plasma configuration, and that alone merits exploration.

[D Tibbets]

And also have a naive idea that plasma in Polywell will be cold or not-thermalized (by your definition). But that is not truth.

We shall see. That is what experiments are for!

Again, you sound confused. Abandon using hot and cold. Us velocity ,or KE if you prefer.

At Tokamak might have a 'temperature that averages 5 KeV, and 90 % of the fusion may occur at the high energy tail (hot in your viewpoint) that exceeds ~ 20KeV.

In a Polywell operating at near monoenergetic conditions, the vast majority of the ions may be at ~ 20 +/- 1 KeV.
In this sense the average temperature is 20 KeV so it is signifficantly 'hotter' than the Tokamak example.
The point is two fold. Essentially all of the ions are participating in fusion, there are few low energy ions (in the core), so you are not wasting input energy in 'heating useless ions, and you have less useless ions that are contributing to losses. On the other hand, if you could heat the Tokamak plasma to an average energy of 20 KeV, the fusion rate may match the Polywell. But now you have even hotter ions in the high energy tail, that while still contributing to fusion, are also contributing to increased containment and loss problems.

When 'cold' is used in the Polywell it is referring to the energy at the potential well peak for the ions and the electrons. Ideally the electrons are 'cold in the core and 'hot' on the edge, while the ions are 'hot' in the core and 'cold' on the edge. Without specifying where in the machine you are referring to, the label of cold, hot, low energy, high energy, etc is not very informative, and can be confusing.

Dan Tibbets

[ltgbrown]

OK, I am not a physicist, but I have a BS in it and I slept at a Holiday Inn Express.

In my mind, the difference between Tokamak and Polywell (and therefore how you think about the plasma within them) is how the energy to overcome the coulomb forces is achieved. Tokamak attempts to do with pressure and temperature and a tiny tail of the Maxwellian distribution. Polywell does it with electrostatic forces and density (i.e. all the ions are accelerated towards a point (ok, not exactly a point but a central region from all sides.)) So, talking about temperature works well, when talking about plasmas under compression. Velocity works well when talking about plasmas being accelerated.

(Actually, I didn't sleep at a Holiday Inn Express, just a regular one and I drank a lot of beer in college, so I could be completely off my rocker.)

[Joseph Chikva]

At Tokamak might have a 'temperature that averages 5 KeV, and 90 % of the fusion may occur at the high energy tail (hot in your viewpoint) that exceeds ~ 20KeV.

In a Polywell operating at near monoenergetic conditions, the vast majority of the ions may be at ~ 20 +/- 1 KeV.
In this sense the average temperature is 20 KeV so it is signifficantly 'hotter' than the Tokamak example.
The point is two fold. Essentially all of the ions are participating in fusion, there are few low energy ions (in the core), so you are not wasting input energy in 'heating useless ions, and you have less useless ions that are contributing to losses. On the other hand, if you could heat the Tokamak plasma to an average energy of 20 KeV, the fusion rate may match the Polywell. But now you have even hotter ions in the high energy tail, that while still contributing to fusion, are also contributing to increased containment and loss problems.

When 'cold' is used in the Polywell it is referring to the energy at the potential well peak for the ions and the electrons. Ideally the electrons are 'cold in the core and 'hot' on the edge, while the ions are 'hot' in the core and 'cold' on the edge. Without specifying where in the machine you are referring to, the label of cold, hot, low energy, high energy, etc is not very informative, and can be confusing.

Dan Tibbets

First
TOKAMAKs developers do not hope on 90% burning-off fuel. But on much less. In Polywell and in other beam devices as well by idea the burning-off should be more. But not 100%. Because in reaction zone gradually will decrease the density of reacting nucleii together with appearance of other charged particles - products of reaction.
Second
The temperature in TOKAMAKs not 5keV but 10 keV reached in latest versions and 15keV projected for ITER.
Third
There is one more difference between beem method (using coherent motion of particles for overcoming barrier) and thermal method: for beam we should spend 100% required for fusion KE before reaction. In thermal methods only high energetic tail of distribution can work initially. That is "ignition". Then by idea self-heating at the expense of fusion. It is not advantage or disadvantage but only the feature of method.
Fourth
I am repeating. Till now I could not see any mechanism allowing to avoid thermalization in Polywell. But thermalization will occur obligatory. As together with each fusion event you will get thousands elastic collisions events as well. So, If you have not any dissipating mechanism better if together with mechanism returning the scattered particle to the right direction, sorry. Because you will not can save your so lovely "mono-energetism"

[cuddihy]

At Tokamak might have a 'temperature that averages 5 KeV, and 90 % of the fusion may occur at the high energy tail (hot in your viewpoint) that exceeds ~ 20KeV.

In a Polywell operating at near monoenergetic conditions, the vast majority of the ions may be at ~ 20 +/- 1 KeV.
In this sense the average temperature is 20 KeV so it is signifficantly 'hotter' than the Tokamak example.
The point is two fold. Essentially all of the ions are participating in fusion, there are few low energy ions (in the core), so you are not wasting input energy in 'heating useless ions, and you have less useless ions that are contributing to losses. On the other hand, if you could heat the Tokamak plasma to an average energy of 20 KeV, the fusion rate may match the Polywell. But now you have even hotter ions in the high energy tail, that while still contributing to fusion, are also contributing to increased containment and loss problems.

When 'cold' is used in the Polywell it is referring to the energy at the potential well peak for the ions and the electrons. Ideally the electrons are 'cold in the core and 'hot' on the edge, while the ions are 'hot' in the core and 'cold' on the edge. Without specifying where in the machine you are referring to, the label of cold, hot, low energy, high energy, etc is not very informative, and can be confusing.

Dan Tibbets

First
TOKAMAKs developers do not hope on 90% burning-off fuel. But on much less. In Polywell and in other beam devices as well by idea the burning-off should be more. But not 100%. Because in reaction zone gradually will decrease the density of reacting nucleii together with appearance of other charged particles - products of reaction.
Second
The temperature in TOKAMAKs not 5keV but 10 keV reached in latest versions and 15keV projected for ITER.
Third
There is one more difference between beem method (using coherent motion of particles for overcoming barrier) and thermal method: for beam we should spend 100% required for fusion KE before reaction. In thermal methods only high energetic tail of distribution can work initially. That is "ignition". Then by idea self-heating at the expense of fusion. It is not advantage or disadvantage but only the feature of method.
Fourth
I am repeating. Till now I could not see any mechanism allowing to avoid thermalization in Polywell. But thermalization will occur obligatory. As together with each fusion event you will get thousands elastic collisions events as well. So, If you have not any dissipating mechanism better if together with mechanism returning the scattered particle to the right direction, sorry. Because you will not can save your so lovely "mono-energetism"

A polywell plasma does NOT behave like a standard beam-beam plasma, because of the strong potential gradient. (which does NOT exist in a standard beam-beam).

A polywell plasma has DISTINCT populations of particles that behave very differently at different points in the polywell.

This is a peice of your confusion. "Thermalization" is NOT avoided in the Polywell. "Thermalization" is in fact maximized, at the edge, where the geometry and electrostatic "hill" ions have had to climb have ensured that it is where the ions are already "coldest" anyway.

The "mechanism returning the scattered particle to the right direction" is the electrostatic potential gradient. No amount of up-scattering is going to overcome the deep potential gradient, for all but the smallest fraction of ions.

[Joseph Chikva]

A polywell plasma does NOT behave like a standard beam-beam plasma, because of the strong potential gradient. (which does NOT exist in a standard beam-beam).

A polywell plasma has DISTINCT populations of particles that behave very differently at different points in the polywell.

This is a peice of your confusion. "Thermalization" is NOT avoided in the Polywell. "Thermalization" is in fact maximized, at the edge, where the geometry and electrostatic "hill" ions have had to climb have ensured that it is where the ions are already "coldest" anyway.

The "mechanism returning the scattered particle to the right direction" is the electrostatic potential gradient. No amount of up-scattering is going to overcome the deep potential gradient, for all but the smallest fraction of ions.

Coherent vs. thermal
Do you know something else?
I do not.

What do you mean "electrostatic gradient" dE/dr or what?
And as I understand the potential well can return particle back to the center (radial direction). And what non zero potential gradient has Polywell when particle declines from the right radial direction? As I think - nothing. Tangential field intensity equal to zero. You have electrostatic field in radial direction and several magnetic mirrors confining the reaction zone.

Also, on my level of understanding thermalization will not be different (temperature gradient) at the edge and in center because there in Polywell particle permanently should walk edge-center-edge before fusion event. It is impossible. You will have temperature gradient also equal to zero or near zero. All the more in case if significant ammount of fusion events will occur. Will not that thermalize remaining particles mainly in center?

[Giorgio]

Joseph, you are again mixing terminology and making assumptions starting from a wrong base.

Let me suggest you that before we continue this discussion we fix the meaning of some terms and we "stick" to them, otherwise we will not get out anything meaningful from this thread.

Is it clear the definition we are using in this forum for Hot, Cold and Thermalized plasma?
Did you read the webpages I gave you the link to?

[Joseph Chikva]

Joseph, you are again mixing terminology and making assumptions starting from a wrong base.

Let me suggest you that before we continue this discussion we fix the meaning of some terms and we "stick" to them, otherwise we will not get out anything meaningful from this thread.

Is it clear the definition we are using in this forum for Hot, Cold and Thermalized plasma?
Did you read the webpages I gave you the link to?

Thanks, Georgio.
I use therms that know.
-Thermalization - this is slangy expression (term)
-Hot - that is having high temperature.
-Cold - that is having low temperature.
-Temperature - the parameter showing the particles' average energy of chaotic motion in distribution
What here is not clear?
Has Polywell community thought up a new terminology?

[KitemanSA]

Has Polywell community thought up a new terminology?

YES!!! dang it.

I use therms that know.

And that is your problem here. We DON'T use the terms that you know. Understand the terms as we use them and you may begin to understand the subject.

-Thermalization - this is slangy expression (term) The process of moving toward a Maxwellian distribution
-Hot - that is having high temperature. having high average kinetic energy
-Cold - that is having low temperature. having low average kinetic energy
-Temperature - the parameter showing the particles' average energy of chaotic motion in distribution has a Maxwellian distribution
What here is not clear? Back at-cha!

[Uthman]

I think we've made breakthrough progress here =]

[Joseph Chikva]

Has Polywell community thought up a new terminology?

YES!!! dang it.

I use therms that know.

And that is your problem here. We DON'T use the terms that you know. Understand the terms as we use them and you may begin to understand the subject.

-Thermalization - this is slangy expression (term) The process of moving toward a Maxwellian distribution
-Hot - that is having high temperature. having high average kinetic energy
-Cold - that is having low temperature. having low average kinetic energy
-Temperature - the parameter showing the particles' average energy of chaotic motion in distribution has a Maxwellian distribution
What here is not clear? Back at-cha!

Really?
Dear Professor,
Are you sure that distribution in Polywell is obligatory Maxwellian? Or you also have invented a new distribution and only use an old name?
High/low average kinetic energy can be considered as addition of energies coherent and chaotic motion. And temperature is only the measure of chaotic.

Temperature has a Maxwellian distribution.

Hehe

[Giorgio]

Are you sure that distribution in Polywell is obligatory Maxwellian? Or you also have invented a new distribution and only use an old name?

You seem not to get it.
We are not sure about anything. The same way you cannot be sure about your model working!
Until proper experiments will be done all we can do is consider the model and try to understand why it should work or should not work.

To do this you need to use the same terminology we are using.
I do not count the times I had harsh discussions here with other people because we define a word in 2 different way.
Anyhow, these are the terms that are used here, so either you stick to them or you will never be able to understand and make the other understand your point of view.