Other technical paper cited above.
really long url
Or you can just read Tom's summary, which says the same thing but without all the pretty numbers and equations.
==
Edited by M. Simon to fix long url.
Picture Of WB-7 Fusion Test Reactor Available
I fully understand the "If you keep the electron cool then they radiate less" argument involved in reducing the anode height to reduce the collissional energy of electrons in the core, the hydrogen rich trick is also legitimate and is even mentioned by Rider.
Its the third issue, the issue of keeping the electron temperature massively lower then the ions in the core, which I have trouble comprehending and possibly agreeing with, if you try to maintain a huge energy difference between electrons and ions the rate at which ions transfer energy to electrons will be massive and prohibitively higher than fusion.
I think Bussard glossed over this issue, in the report I read, far to quickly without elaborating any of the details he used in his calculation.
I believe the basic argument is that the ions heat the electrons in the core, the electrons cool the ions at the edge.
Without a more eleaborate justification for this (maybe one exists, but I have to see it and understand the assumptions it incorporates into it) it just doesn't seem to hold water for me, as there is a fundamental assymetry involved here:
When the ions transfer energy to the electrons in the core the plasma density and thus the rate of collissions is very high, yet when the electrons transfer energy back to the ions at the edge the plasma density, and thus the rate of collissions is much (X10,000) lower. In addition to this, it is the electron temperature, for the most part controls the rate of collissions (unless the ion temperature is 1840 times higher than the electrons) between ions and electrons. This rate is proportional to the inverse of the electron temperature to the power of 3/2, thus when the electrons are at a lower velocity in the core, the rate of energy transfer from ions to electrons will be massively higher than the converse rate of energy transfer from electrons to ions in the edge where the electron temperature is high, in addition to this, electrons will spend much more time in the core than the edge this compounds the problem still further (if it wasn't compounded enough as things were)
I can believe Krall's argument for ion annealing maintaining a monoenergetic distribution of ions beyond the ion-ion collission time, that could possibly work. But the transfer of energy from ions to electrons, which was the main thrust of Riders thesis and critique, exceeding the fusion time, is an issue which has been completely sidestepped in this paper and has not been resolved in any conceivable sense of the word.
Its the third issue, the issue of keeping the electron temperature massively lower then the ions in the core, which I have trouble comprehending and possibly agreeing with, if you try to maintain a huge energy difference between electrons and ions the rate at which ions transfer energy to electrons will be massive and prohibitively higher than fusion.
I think Bussard glossed over this issue, in the report I read, far to quickly without elaborating any of the details he used in his calculation.
I believe the basic argument is that the ions heat the electrons in the core, the electrons cool the ions at the edge.
Without a more eleaborate justification for this (maybe one exists, but I have to see it and understand the assumptions it incorporates into it) it just doesn't seem to hold water for me, as there is a fundamental assymetry involved here:
When the ions transfer energy to the electrons in the core the plasma density and thus the rate of collissions is very high, yet when the electrons transfer energy back to the ions at the edge the plasma density, and thus the rate of collissions is much (X10,000) lower. In addition to this, it is the electron temperature, for the most part controls the rate of collissions (unless the ion temperature is 1840 times higher than the electrons) between ions and electrons. This rate is proportional to the inverse of the electron temperature to the power of 3/2, thus when the electrons are at a lower velocity in the core, the rate of energy transfer from ions to electrons will be massively higher than the converse rate of energy transfer from electrons to ions in the edge where the electron temperature is high, in addition to this, electrons will spend much more time in the core than the edge this compounds the problem still further (if it wasn't compounded enough as things were)
I can believe Krall's argument for ion annealing maintaining a monoenergetic distribution of ions beyond the ion-ion collission time, that could possibly work. But the transfer of energy from ions to electrons, which was the main thrust of Riders thesis and critique, exceeding the fusion time, is an issue which has been completely sidestepped in this paper and has not been resolved in any conceivable sense of the word.
My understanding is they do not. Unless the virtual anode is too strong, they tend to see the positive magrid and spend most of their time crowding the edge of the magnetic field trying to get to it. At least, that's how I've always pictured it.in addition to this, electrons will spend much more time in the core than the edge this compounds the problem still further.
This is one of those things that might only be resolvable by experiment.
A lot of this will require experimentation. With a working Polywell running deuterium, it should be possible to validate some of the models. Let's hope Dr. Nebel and company succeed.
Presuming our rnebel poster really is Dr. Nebel, he recently posted that the ion focus in a Polywell is not so sharp as some of us may be supposing. I do recall some potential well plots that were more like a fat post-hole than a parabolic well. If it runs acceptably well somewhat defocussed, that might reduce some density-related problems associated with a very sharp convergence radius.
Presuming our rnebel poster really is Dr. Nebel, he recently posted that the ion focus in a Polywell is not so sharp as some of us may be supposing. I do recall some potential well plots that were more like a fat post-hole than a parabolic well. If it runs acceptably well somewhat defocussed, that might reduce some density-related problems associated with a very sharp convergence radius.
Jaeyoung is out in the lab right now doing the fusion thing. As you might have noticed, we are trying to open things up a bit and I thought it might be good to get to know you bloggers a little better. We have been very quiet the last few months primarily because we were trying to fly under the radar from the Office of Fusion Energy Sciences from the DOE. That all went out the window with Alan Boyle's latest MSNBC blog two weeks ago. Fortunately, we're far enough along now that they won't be able to shoot us before we get the answers from the WB-7. Although their original response was rather nasty, we are trying not to have an adversarial relationship with them. I have known a lot of the OFES people for a long time, and I hope we have convinced them that we are just trying to do an honest job with our program.
If it is OK with you, I may chime in from time to time on your blog. However, this is your forum and I don't want to stick my nose in too heavily.
If it is OK with you, I may chime in from time to time on your blog. However, this is your forum and I don't want to stick my nose in too heavily.
Dr. Nebel,
I can't speak for the site owner but, as one of the moderators we are honored to have you here.
Let me add - from private conversations I have had with a number of people - there is a huge (relative to the size of the project) talent pool that has been self educating and is ready to assist in any way possible to move this forward.
I had mentioned in a blog post that I was willing to sweep the floors to move the project forward. A commenter chimed in that he was ready to clean the loos.
My expectation from various sources is that when WB-7 shows a need for more work by a number of groups (a period of inflation if you will) there will be a number of people who are self trained in Polywell ready to hit the ground running.
The dedication I see reminds me a lot of the early days of the microprocessor revolution that started in Jan '75 with the publication in Popular Electronics of the Altair article.
Our equivalent was the posting of the Google Tech Talk by Dr. Bussard in Nov. '06.
For months after that me and a small band of people (thanks to Tom Ligon's help at NASA Spaceflight) were relentless going around the 'net educating people to form a constituency. Now a days I will get notifications of discussions of fusion and people I never heard of are giving competent explanations of Polywell.
In a way it is like something out of Star Wars. Some insignificant event changes every thing. Let me add that I owe my initial interest to Justin and Eric of Classical Values blog who introduced me to the video.
I can't speak for the site owner but, as one of the moderators we are honored to have you here.
Let me add - from private conversations I have had with a number of people - there is a huge (relative to the size of the project) talent pool that has been self educating and is ready to assist in any way possible to move this forward.
I had mentioned in a blog post that I was willing to sweep the floors to move the project forward. A commenter chimed in that he was ready to clean the loos.
My expectation from various sources is that when WB-7 shows a need for more work by a number of groups (a period of inflation if you will) there will be a number of people who are self trained in Polywell ready to hit the ground running.
The dedication I see reminds me a lot of the early days of the microprocessor revolution that started in Jan '75 with the publication in Popular Electronics of the Altair article.
Our equivalent was the posting of the Google Tech Talk by Dr. Bussard in Nov. '06.
For months after that me and a small band of people (thanks to Tom Ligon's help at NASA Spaceflight) were relentless going around the 'net educating people to form a constituency. Now a days I will get notifications of discussions of fusion and people I never heard of are giving competent explanations of Polywell.
In a way it is like something out of Star Wars. Some insignificant event changes every thing. Let me add that I owe my initial interest to Justin and Eric of Classical Values blog who introduced me to the video.
Engineering is the art of making what you want from what you can get at a profit.
-
Average Joe
- Posts: 18
- Joined: Fri Jan 25, 2008 8:48 pm
- Location: Maryland
Dr. Nebel, I'm nobody and you don't know me, but this kind of makes my blood boil. The way I read that is that there are people who are so interested in their own turf dominance that they would suppress a chance to just maybe revolutionize history. I can't understand that kind of evil. Your statement has really energized me. I wish I had some direction for that energy to go.Although their original response was rather nasty, we are trying not to have an adversarial relationship with them.
MSimon: Wow, you REALLY hit it on the head for me with that statement. I was just in high school in '75 and didn't get my hands on an IMSAI 4040 until I went to college. Then I subscribed to every PC magazine I could get my hands on and read every word. This feels just like that. If Dr. Nebel and his team are successful I will have to find SOME way to change careers.The dedication I see reminds me a lot of the early days of the microprocessor revolution that started in Jan '75 with the publication in Popular Electronics of the Altair article.
Joe
-
Average Joe
- Posts: 18
- Joined: Fri Jan 25, 2008 8:48 pm
- Location: Maryland
Of course! Who could forget it?
No, not really. I've always been a software guy, not hardware. Well hardware only to the point of getting a machine to do software on. I do remember Kilobaud Microcomputing though. And Byte. I kept every issue of Byte for years. In fact I rediscovered Jerry Pournelles's website recently while looking for BFR references.
No, not really. I've always been a software guy, not hardware. Well hardware only to the point of getting a machine to do software on. I do remember Kilobaud Microcomputing though. And Byte. I kept every issue of Byte for years. In fact I rediscovered Jerry Pournelles's website recently while looking for BFR references.
Joe