Posted: Tue Jun 12, 2012 7:52 pm
Have you read up on project history yet?
a discussion forum for Polywell fusion
https://talk-polywell.org/bb/
Polywell is not isotropic X-Y-Z. It is a beam-beam machine (6 beams actually). This is a very common confusion for beginners (mixing up thermal and beam machines), don't feel all alone.2) to be fair, for 3-D isotropic maxwellian plasma, the energy for any X-Y-Z direction should be about 1/3 of the value you used.
My understanding of polywell isnt enough to answer the earlier points, but those on this website who do understand this machine on the thermal dynamic level, how energy sharing, particle behavior, etc in this machine can probably answer your questions.emc3 wrote:Compare to toks, at the level of T-1 or T-3, early WBs' engineering could be simple, but the physics are not: it's way way too complicatedIf some lobbyist tell us that he or sb else understand the wiffleball mechanism, be aware of "The Emperor's New Clothes".
-ishIt is a beam-beam machine (6 beams actually).
ladajo wrote:Have you read up on project history yet?
Actually no.... instabilities, at least the unique ones in toks, are not present in stellerators, sorry... Again, you miss my point and also the primary concern of mainstream torodial magnetic confinement community. Again, control is the issue, because of the micro and macro instabilities. We've moved past the Lawson Criterion long ago, it's the simplistic way of looking at plasma confinement.Joseph Chikva wrote:"Toks lasting minutes" are overcoming Lawson Criterion (product of number density and confinement time). Modern toks do that but can not overcome triple product (product of number density and confinement time and temperature). So, denying by you (and your professors) heating problem is the most significant problem for TOKAMAKs.Robthebob wrote:Again, I'm not saying toks cant last into the minutes,...It does not matter in what you are sure but after doubtless success of TOKAMAKs stellarator program in USA was cancelled. That is the fact that is much more significant than my, yours or any others opinion.Robthebob wrote:I'm sure they can, so can stellerators,...May be you would be surprised but they (instabilities) are occurring in ANY plasma device.Robthebob wrote:but I'm saying it doesnt matter how long you toks can last, if instabilities happen, then what?
But once again if lifetime of plasma in TOKAMAKs reaches seconds, they are rather controllable in TOKAMAKs. Unlike any other devices.
PS> You wrote too long text. It is rather difficult for me to answer on each little sentence from there. Sorry.
A lot of it is our fault, many of us have been following polywell for years. I guess it also didnt help that questions and concerns sounded like accusations from your posts.emc3 wrote:I am reading ......
Be nicer and patient, please.
ladajo wrote:Have you read up on project history yet?
Toks are in the first place because they give better perfomance.Robthebob wrote:Also, you dont seem to understand why toks were made in the first place. They were made because 1. they're easier to design and build, 2. they allowed for higher plasma density and temperature given the same amount of effort (usually), 3. pulsed machines didnt matter because studying the physics in time frames of milliseconds and 10s of seconds do not differ, the life time of plasma is short enough that a plused machine can be used to study the physics no problem.
100% chance of no disruption is impossible in engineering. Regardless to parameters. Good luck.Robthebob wrote:The car can go on for a long time, but can you guarantee that the car will never ever break down? Imagine now that, this breaking down process happens even more often, and if you're building a power plant, how can you afford a disruption, ever? It literally has to be like 100% chance of no disruption or 100% of time, you can either avoid the disruption from growing, deal with it somehow, or stay away from parameters that would cause disruptions.
The available documents address a good bit of your questions if you read them carefully. Once you have read them, and then go through public commentary by project participants, I think it will help you understand what they have done, how, and where they are at now. It is a lot to get through, and some refuse to do it.emc3 wrote:I am reading ......
Be nicer and patient, please.
ladajo wrote:Have you read up on project history yet?
Get your facts straight please, toks are not steady state machines, it's evident in the fact that you cant have a continuously changing current running through the transformer coil forever, well you can change directions, I dont know how that would work. That itself is enough to warrant the statement that it's impossible to have a tok power plant. No such a thing as long pulse machines, you can make the pulse last longer, but it doesnt matter. The longer the operation, the greater the amount of the current through the coils. Again, they're not "first place" (what are we? children competing for attention?). There are more of them because they make studying physics at those conditions easier, but once again, it's funny, because what makes toks reach those conditions easier is what's killing toks. I absolutely do not understand what you mean by "long pulse machine." A pulse machine is a pulse machine is a pulse machine is a pulse machine, as in it cant operate for indefinite durations.Joseph Chikva wrote:Toks are in the first place because they give better perfomance.
Toks also are pulse machines. But long pulse machines.
Pulse machines do matter as second epproach seriously considered by mainstream physics is inertial confinement driven by lasers or beams. Pulse duration there has microseconds order.
Your statement that Stelarators have not instabilities is wrong. Microinstability studies for the large helical device
http://infoscience.epfl.ch/record/119892
Among some MHD instabilities, the ballooning instability is closely related with the β-limit of a helical device such as the large helical device. (LHD) http://ieeexplore.ieee.org/xpl/login.js ... %3D5944975 etc.
I know about existence of only two actual stellarators: LHD in Japan and the second Waldenstein (or similar name) in Germany. What's name of machine being in your school?
100% chance of no disruption is impossible in engineering. Regardless to parameters. Good luck.
B varying from -5 to +5 T allow to keep 0.5-2 V loop voltage for many seconds. By the end of induction pulse the so called bootstrap current begins lasting as long as required. This is proved experimentally that several amperes order beams drive migamperes order current in plasma.Robthebob wrote:Get your facts straight please, toks are not steady state machines, it's evident in the fact that you cant have a continuously changing current running through the transformer coil forever, well you can change directions, I dont know how that would work. That itself is enough to warrant the statement that it's impossible to have a tok power plant.
I understand that you believe only your proffesors but e.g. DOE believes only in TOKAMAK and inertial confinement driven by laser (NIF) or heavy ion beam. Pulse duration there is much shorter than in TOKAMAKs.Robthebob wrote:That itself is enough to warrant the statement that it's impossible to have a tok power plant.
30 years ago even 1 sec of plasma lifetime was an unrealizable dream. As in case of enough plasma reactivity which is first of all the temperature function, 1 sec is quite enough.303 wrote:and cant even get stable plasma for longer than a few minutes,