Focus Fusion news story

[tomclarke]

So, if single electron moves across an electric potential difference of one volt that gains the 1 eV
Does for that electron "temperature" make sense?

Well, for example:

The high temperatures attained by explosive release of chemical energy derive from the +few eV energies of valence electrons in the explosive constituents compared to same in the explosive products.

A few ev = 10,000K+?

Sure it makes sense.

[Joseph Chikva]

It is true that technically the temperature of a coherent mono-energetic high energy beam can be low (and, more technically, relativity shows that mono-energetic beams are at some level equivalent to stationary particles).

Not “technically low” but totally low temperature. Motion in beams has two components: coherent and thermal. When coherent component is much higher (55 keV vs. 1-2 eV in that example) we have a right to speak about coherent system.

Add a monoergetic coherent beam (for simplicity of the same particles) of energy E1/particle. The beam consists of M particles (so we can be quantitative).

Assume that after some time the system equilibrates to a Boltzmann KE distribution.

Conservation of energy within the box tells you, trivially, that the temperature of the box is now (E0N+E1M)/(N+M).

From which we derive an effective temperature for the monoenergetic beam (in this context) of T1 = E1/k as everyone here except ypou would expect.

There is no necessity in such assumptions (“system equilibrates to a Boltzmann KE distribution”) and in invention of new non-standard term of effective temperature. As all is thought out many many years ago by people who were more qualified than you and me.
Simply if we would input the energy into certain media (e.g. background plasma) injecting there beam, temperature of that media increases, coherent component of beam decreases while thermal component increases. And we can speak about thermalization of beam when its thermal component will become comparable with coherent.
We would be right to use this term thermalization for any such process: low thermal + high coherent => thermal comparable with coherent.
Regardless to that did such system reach thermal equillibrium or not.

Now again about temperature.
Not on your non-standard term of "effective temperature" but on its classical understanding.
When thermal component increases, so increases the temperature of system. And what is it? This is heating, my friend.

Thanks.

[Joseph Chikva]

So, if single electron moves across an electric potential difference of one volt that gains the 1 eV
Does for that electron "temperature" make sense?

Well, for example:

The high temperatures attained by explosive release of chemical energy derive from the +few eV energies of valence electrons in the explosive constituents compared to same in the explosive products.

A few ev = 10,000K+?

Sure it makes sense.

I have a little kittycat but call it "tiger". You can justify anything said here and I can agree with you but this would not improve a very specific understanding of thermodynamics of some people here.

Added:
http://en.wikipedia.org/wiki/Boltzmann_constant

The Boltzmann constant, k, is a bridge between macroscopic and microscopic physics, since temperature (T) makes sense only in the macroscopic world, while the quantity kT gives a quantity of energy which is on the order of the average energy of a given atom in a substance with a temperature T.

So, for a single particle term "temperature" does not make sense.

[MSimon]

MSimon is a huge proponent of free speech though.

Not just me. Joe - who started the board - insists I only deal with spam and mechanical issues = pictures too big, urls too long and not touch the text at all otherwise. I have only deleted one post by accident in the last 5 years and that was 3 or 4 years ago,

Joe's thinking and mine coincide. We did have a nut here a while back who couldn't get his hands around that I was not a content moderator. Just the janitor. It didn't fit his model. When he figured out he wasn't being censored and that I was not in control - he left. People is strange.

[MSimon]

Joe,

If you have one unit in your sample the average energy is the energy of that unit.

And now here is the killer. Since the Polywewll is a colliding beam machine and not a crock pot like Toks - you can talk about the average energy - but temperature is not a useful concept when dealing with beam machines.

So yes. Average energy does apply. But it doesn't help in understanding the concept. As you have so cleverly pointed out.

[Joseph Chikva]

Joe,

If you have one unit in your sample the average energy is the energy of that unit.

And now here is the killer. Since the Polywewll is a colliding beam machine and not a crock pot like Toks - you can talk about the average energy - but temperature is not a useful concept when dealing with beam machines.

So yes. Average energy does apply. But it doesn't help in understanding the concept. As you have so cleverly pointed out.

Thank you MSimon.
I do not see on Polywell as on "colliding beams machine". As beams there are used for forming of virtual cathode.
And when people say “colliding beams”, usually they mean colliding beams of ions making fusion as result of collisions.
But that is only name issue.
Best regards,
Joseph

[ladajo]

So what in the world have you been arguing about "Beams" for more pages than I am bothered to count???

Just the electron stream into the core? Which, by the way, is probably not neccessary in a fullscale machine using two-color start up or full on stripping...

[MSimon]

So what in the world have you been arguing about "Beams" for more pages than I am bothered to count???

I thought it was pretty slick to let him go on for pages and spring that on him.

I guess he doesn't accept his own logic. He is not the only one.

[Joseph Chikva]

So what in the world have you been arguing about "Beams" for more pages than I am bothered to count???

Just the electron stream into the core? Which, by the way, is probably not neccessary in a fullscale machine using two-color start up or full on stripping...

Just the electron stream into the core? Yes. As if we talk about two-stream instability, electronic beam much more vulnerable than e.g. beam of neutral deitons used for plasma heating in TOKAMAKs.

Charged Particle Beams
Stanley Humphries, Jr.
Department of Electrical and Computer Engineering
University of New Mexico
Albuquerque, New Mexico
Originally published in1990 by John Wiley and Sons

Two-stream instabilities are a major concern when beams propagate through plasmas. Examples include long-distance propagation of high energy electron beams, transport of low-energy ion beams emerging from high-current injectors, and the propagation of heavy ion beams in an inertial fusion reaction chamber. The two-stream instability may be desirable in applications such as plasma heating by intense electron beams.

[Joseph Chikva]

I guess he doesn't accept his own logic. He is not the only one.

Also my feet are braided when walking.

[MSimon]

I guess he doesn't accept his own logic. He is not the only one.

Also my feet are braided when walking.

Clever. Could you explain how it is done?

[mvanwink5]

You guys crack me up!
Best regards