Joined: May 17, 2005 Posts: 386 Location: Northeast Ohio
Posted: Sat Dec 16, 2006 10:32 am Post subject: Polywell Fusion Reactor
Came across this today, I thought it was pretty neat.
Quote:
Polywell is a gridless inertial electrostatic confinement fusion process designed by Robert Bussard under a Navy research contract, designed to overcome the losses in the Farnsworth-Hirsch fusor and create a breakeven fusion reactor.
Posted: Sat Dec 16, 2006 1:56 pm Post subject: Re: Polywell Fusion Reactor
There is another thread on the topic of Bussard. "Should Google Go Nuclear?" That thread links to a google video of Bussard giving a presentation about his fusion reactor research.
Posted: Sat Dec 16, 2006 2:24 pm Post subject: Re: Polywell Fusion Reactor
Yeah, it definitely was a sales pitch to the guys at Google. It started out real slow but picked up steam as he got further into it, talking about the testing itself.
I don't have the background to evaluate the validity of his claims, but he does explain what that shiny thing is for, and why it is toroids arranged as a polyhedron.
Robert W. Bussard (born 1928) is an American physicist working primarily in nuclear fusion energy research. Recipient of the Schreiber-Spence Achievement Award for STAIF-2004. Fellow of the International Academy of Astronautics.
In 1960, Bussard conceived of the Bussard ramjet, an interstellar space drive powered by hydrogen fusion using hydrogen collected using a magnetic field from the interstellar gas. Due to the presence of high-energy particles throughout space, most interstellar hydrogen exists in an ionized state that can be manipulated by magnetic or electric fields. Bussard proposed using a large magnet to "scoop" up the ionized hydrogen and funnel it into a fusion reactor, using the exhaust from the reactor as a rocket engine. Since it picked up its fuel from space, there was no apparent upper limit to the speed such a craft could achieve. However it appears the "energy gain" in the reactor must be extremely high for the ramjet to work at all; any hydrogen picked up by the scoop must be sped up to the same speed as the ship in order to provide thrust, and the energy required to do so increases with the ship's speed.
Atomic Energy Commission
In the early 1970s Bussard became Assistant Director under Director Robert Hirsch at the Controlled Thermonuclear Reaction Division of what was then known as the Atomic Energy Commission. They founded the mainline fusion program for the United States: the Tokamak. Later, in June 1995, Bussard claimed in a letter to all fusion laboratories as well as to key members of US Congress, that he, along with the other founders of the program, supported the Tokamak not out of conviction that it was the best technical approach but rather as a vehicle for generating political support, thereby allowing them to pursue "all the hopeful new things the mainline labs would not try"...
This guy is no fly-by-nighter. And the sort of investors he is appealing to are not people like you guys, so you need not worry about whether or not to invest in it.
Bussard is trying to raise $150-200 million to answer the next set of questions on the way towards ultimately determining the feasibility of building a large-scale fusion reactor of the inertial confinement type.
So he is trying to reach funders/venture capitalists who all know implicitly the huge challenges involved and the likelihood that the money could just evaporate. The main attraction, of course, is the idea inherent in the EMC2 equation - that just a very small amount of matter can potentially yield unimaginable amounts of energy. It's worth pursuing anyway!
Bussard's point is that the governments of the world who are funding the major fusion reactor project in France are taking a "group think" approach of the kind that typically do not produce results, this from someone with a background at the Atomic Energy Commsission. Rather, he says, the fusion project will end up being populated by little scientific lords each controlling his own scientific fiefdom that continually engages in research but never produces anything.
The funds involved in the government-sponsored fusion project are in the multi- billions. By this standard, a couple of hundred million is chump change and can be applied to a project which actually strives to produce real results in the style of science that used to take place in the days of Tesla and others.
In any such pitch, the question of vetting the science naturally arises and so the sponsors of the project must have it vetted properly for those who are perhaps interested in contributing towards it. However, only a handful of people in the world would understand the details of the science/engineering involved. Investors must see a project like this vetted by one of these people and that was brought up in the presentation.
Brussard approached Google not only because of its deep pockets but also because pitching the plan to them raises the profile of his fund-raising efforts tremendously. And by doing so, he hopes to reach the right people.
So you need not warn Grandma about him!
If you find this interesting, you can increase your basic knowledge of the competition to find viable fusion energy here:
* Details the initial discovery of nuclear fusion, all related research, and today's concern over future energy supply
* Examines current attempts to create nuclear fusion here on earth
* Enhanced with color illustrations and examples
* Provides a non-technical treatment of fusion using straightforward language
* Includes technical notes for aspiring physicists
This electronic book on CD-ROM provides comprehensive coverage of every aspect of research into nuclear fusion technology and the race to develop a fusion energy power plant reactor. There is complete information about experimental facilities, research programs, and laboratories, including the latest work on magnetic and inertial confinement designs, tokamaks, stellarators, lasers, and plasma physics research. Every major facility in use, under development, or proposed for development is profiled: DIII-D, NSTX, ITER, FIRE, AIRES, and many others. Everything from basic concept descriptions for the layman to highly technical material for scientists is included.
Posted: Sun Dec 17, 2006 10:46 am Post subject: Re: Polywell Fusion Reactor
ElijahJones wrote:
Quote:
I have thought about the field geometry issues myself, the problem is you are trying to contain a reaction that in the sun is caused by the inward pull of gravity, not a containment. Create a magnetic field that has that approximates that and you are getting warm. But those types of configurations can be examined using mathematical software and some PDE's, you don;t need to build a 200 million dollar reactor to see if you can construct the right type of magentic field geometries. That is my problem with this. This whole damn thing should be able to be modeled using simulations at a cost so much less than building it.
Design Considerations from Computer Simulation Codes
Device and system operation and performance at startup conditions, at very early times, have been modelled by complex elextrostatic computer codes, that determine the coulombic interactions between all particles throughout the system and plot trajectories and densities in the system. Results of these computations show conclusively that B-field intercepts with containing structures ensures excessive losses of electrons, as previously discussed. However, these early-time computed results do not show the realistic effects of collective phenomena beyond startup (from low- to high-beta).
These have been readily modelled successfully by a major plasma phenomenological code (the EIXL code) developed by EMC2 since 1990. This is a 1.5-dimensional Vlasov-Maxwell code, in which diamagnetic expansion of B fields is included, particle collisions are estimated from density and energy distributions, fusion rates and output are calculated and bremmstrahlung losses are included, and which includes such phenomena as central core inertial-collisional-compression effects which can apply to core ion compression in Polywell devices. Figures 14 and 15 summarize this code and give a sample output for a pB11 system.
My impression is that Bussard thinks he already has solved almost all the problems associated with this type of fusion. The $200 mil is for an actual pilot plant, not for more experiments.
Regards,
M.R.F. _________________ "... coal and oil were depleted... increased demands for food cut off conversion of the agricultural surplus into fuel alcohol... solar power... as much a dream as atomic energy..." - Jack Williamson, "The Crucible of Power" (1939)
Posted: Sun Dec 17, 2006 10:59 am Post subject: Re: Polywell Fusion Reactor
ElijahJones wrote:
Yeah his credentials are impeccable. But so were Tesla's just before he exposed himself to several large EM bursts and started claiming aliens had visited him.
$200 millions is not much to give his idea a go.
It may even work...
Bussiness potential enormous...and we are not going to run out of 11B before our Sun go red giant...
And a lot of money from ITER could be saved as well.
Joined: May 17, 2005 Posts: 386 Location: Northeast Ohio
Posted: Sun Dec 17, 2006 3:33 pm Post subject: Re: Polywell Fusion Reactor
I have to agree, looking at the rest of the US budget, 200 million is a piss in the proverbial pot. Pentagon spends that much on a toilet and a new microwave for the cafeteria. I am waiting on my dad's reply to an email I shot him, as I only have a rudimentary physics education, he's the PHD. He also has a good nose for smelling BS energy schemes. From what I can tell though, this seems like it could be a step in the right energy direction. Does it help with our current energy woes? Well I think we all know the answer to that. _________________ Reality is agreed perception. Unfortunately there is also a reality imposed by nature.
www.peakoilchat.com - Web based IRC chat, nothing to install!
Posted: Sun Dec 17, 2006 4:38 pm Post subject: Re: Polywell Fusion Reactor
He says in the presentation to Google that the money is needed to answer the next set of questions about developing a large-scale fusion plant.
He gives the strong impression that the physics has been solved for at least break-even energy return. However, the engineering involved in developing a large plant itself presents problems that need to be solved. What he wants is a small pilot project. _________________ "May you live in interesting times"
Posted: Sun Dec 17, 2006 5:04 pm Post subject: Re: Polywell Fusion Reactor
The US is happy to contribute to the $12 billion International Thermonuclear Experimental Reactor being built in France. A project in which it is only a bit player (the US will contribute approximately $1 billion).
If Bussard is right then the $200 million he is asking for is a bargain. It could be worth a roll of the dice.
Posted: Wed Jan 03, 2007 7:16 am Post subject: Re: Polywell Fusion Reactor
kokoda wrote:
It looks nice and compact ... could fit in my car.
Just like Mr Fusion in "Back to the Future".
However one thing that is always said about nuclear fusion is that the technical problems always seem to be about 50 years away from being solved.
Certainly it is an idea worth researching but there won't be any working fusion power reactors anytime soon.
That's a prototype which did not quite operate at "break even" and it has to be inside a vacuum chamber (which is filled with deterium at something like 2-3 Torr). The vacuum chamber used in the tests was too big to fit in a car. According to the inventor, the unit needs to be a couple of meters across to get usable output, so this is an idea for power reactors, not cars.
Posted: Wed Feb 07, 2007 10:58 am Post subject: Re: Polywell Fusion Reactor
Hello, I thought I might be able to clear up some confusion regarding the Polywell device (though I am new here, I'm by no means new to the science).
Polywell is not a magnetic containment device! The toroidal faces of the polyhedron are full of coils which create a quasi-spherical magnetic field. The purpose of the field is not to contain fuel ions (as per the tokamak), but only to confine electrons in the central area of the device. Why, you may ask? Because having a lot of electrons in the centre, which can be relatively easily confined with a magnetic field creates a huge electrical potential gradient between the inner and outer regions of the device. Fusion fuel ions are injected into the apparatus, and they fall into the potential well created by the trapped electrons. Most of the time, they shoot straight through the core (and since the chances of collision with an electron are *miniscule*) and whizz out the other side to repeat the process in a recirculating fashion.
Sometimes, however, two ions will collide and fuse, and the kinetic energy of the fusion products escaping the reactor can be turned directly into electrical energy by appropriate grids placed outside the reactor. In essence, Polywell is the evolution of the Farnsworth-Hirsch fusor, which was doing small-scale fusion long before tokamak research was common, and was invented by Philo T Farnsworth, the inventor of electronic television. By removing the grids from the fusor, and instead creating the confining electrical potential with electrons, there are no grids for recirculating fuel ions to strike and thermalize, so there is much less wasted power.
With sufficient field strength and well depth, it is possible to break even with this device. The real beauty is that it might even be made to make aneutronic fusion work (proton + boron 11). D + D or D + T are all fine and good, but you don't want induced radioactivity in your equipment caused by fast neutrons if possible. There are good physics reasons why this device must be at least a certain size, so you'll never power your car with it, but a ship, submarine or spacecraft are well within the ballpark.
I need hardly add that Bussard's credentials are also impeccable - he has worked for the government and in fusion research most of his adult life.
I also like the fact that he's famous enough to have a part of the starship Enterprise named after him too :D
Posted: Wed Feb 07, 2007 11:21 am Post subject: Re: Polywell Fusion Reactor
Jbat001 wrote:
With sufficient field strength and well depth, it is possible to break even with this device. The real beauty is that it might even be made to make aneutronic fusion work (proton + boron 11). D + D or D + T are all fine and good, but you don't want induced radioactivity in your equipment caused by fast neutrons if possible. There are good physics reasons why this device must be at least a certain size, so you'll never power your car with it, but a ship, submarine or spacecraft are well within the ballpark.
I need hardly add that Bussard's credentials are also impeccable - he has worked for the government and in fusion research most of his adult life.
I only wander, why there is such a problem with paying for initial working proof of concept?
After all $200 million, what he is calling for could even be afforded by Mongolia, Zimbabwe or Dominicana Republic.
There is even plenty of individuals rich enough to undertake such research sponsoring as a hobby with potentially enormous gain, if successful.
I suspect, there are some deep engineering problems there, likely related to handling of high voltages/currents in relatively "congested" space of his fusor....
I have in mind intractable combination of giant arcs, sparks, coronary discharges, stray electron/ion beams etc, which can make our $200 million fuser working as one time use, "disposable" device, or at best, as something, what will need expensive general overhaul every few weeks or so.
NB. You will have to produce at least 2 X more of thermal energy, than thermal breakeven point, if you want to send some excess into the grid.
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