Bussard's fusion work - the "Polywell" looks VERY promising

[Crispy]

Some people might recognise the name. He designed the Bussard Ramjet, a hypothetical interstellar nuclear rocket. Fewer people will know that he was also instrumental in the development of the only genuine nuclear rocket engine, the NERVA. He also kicked off fusion research, sitting on the original research team that started the project that is now called ITER, which proposes a collosal toroidal plasma reactor, which will cost $16b to build.

Over the last 11 years, however, he has been working on another method of fusion. Funded by the US Navy, his proposed fusion machine would be a 3m cube and would generate 100MW using boron as fuel. No hazardous waste, no neutrons spewing out all over the place.

His last prototype before funding was cut generated 100,000 times the power of previous designs of the type. It confirms the theories and the physics works. This is not like cold fusion, where the physics was shaky. In this case, the physics is sound, all that remains is engineering.

But, he's 78 and ill, and low on funds. Only a handful of people are as knowledgeable about fusion and high-energy plasmas as Dr. Bussard. Fingers crosesd, something can be built before he dies.

http://video.google.com/videoplay?docid=1996321846673788606
this is a presentation given by Dr. Bussard last year. It is only since the Navy cut funding that he has been able to publish the research.

http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=5367&start=1
This is an excellent thread at nasaspaceflight, where Dr. Bussard's assistant and co-researcher, Tom Ligon, gives far more details and progress reports.

This looks very promising. Far more so than any other fusion/free energy research I've ever heard of.

 

[Bob_the_lost]

Very cool, almost enough to make you wish you'd kept on with physics.

 

[Jonti]

Inertial confinement, eh?

*crosses fingers

PS that second link takes one into the middle of the thread
http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=5367&start=1
will show the first page

 

[Crispy]

For those who want a simple explanation, the machine consists of 6 ring-shaped magnets, each on the face of an imaginary cube. The combined magnetic field is very strong in the exact center. Electrons are introduced, and they huddle in the center of the field. Next, ions of the reactant are introduced. Bing positively charge, they fly into the center, attracted by the electrons. Most of the time, they fly straight through, loop back out and back in again. But sometimes, one will hit another ion coming the other way - so hard that they first fuse, then spilt, releasing energy. The key innovation is the arrangement of the magnets, which prevents the 'orbitting' ions from colliding with any of the solid apparatus and thus losing energy.

The prototypes show that the physics works, and that a larger version will produce more energy than it takes to run the magnets. Boron is plentiful too.

The other really great thing is that the energy output can be transformed directly into electricity with a 80-95% efficiency, without having to mess about with steam and turbines.

You could also use one to heat a reaction mass, say water, and build a rocketship powerful enough to take off, fly to the moon, land, take off, return to earth and make a powered descent (avoiding high-speed re-entry) in one stage, with no refuelling.

 

[Jonti]

Here's a background article ...
http://www.defensenews.com/story.php?F=2584496&C=america

How It Works

His fuel of choice is one of the earth’s most common and least exotic elements: boron.

It can be scooped from the Mojave Desert in California, possibly even extracted from sea water. Boron is used in the production of hundreds of products as diverse as flame retardants, electronic flat panel displays and eye drops.

It’s so common that no country, company or individual could corner the market on the fuel supply, Gay said.

The process Bussard hopes to perfect would use boron-11, the most common form of the element. Bussard says his experiments — which achieved fusion with deuterium, not boron — in November 2005 proved that the boron process will work.

The boron reactor would be similar to, but more powerful than, the reactor that blew up in 2005.

Bussard’s reactor design is built upon six shiny metal rings joined to form a cube — one ring per side. Each ring, about a yard in diameter, contain copper wires wound into an electromagnet.

The reactor operates inside a vacuum chamber.

When energized, the cube of electromagnets creates a magnetic sphere into which electrons are injected. The magnetic field squeezes the electrons into a dense ball at the reactor’s core, creating a highly negatively charged area.

To begin the reaction, boron-11 nuclei and protons are injected into the cube. Because of their positive charge, they accelerate to the center of the electron ball. Most of them sail through the center of the core and on toward the opposite side of the reactor. But the negative charge of the electron ball pulls them back to the center. The process repeats, perhaps thousands of times, until the boron nucleus and a proton collide with enough force to fuse.

That fusion turns boron-11 into highly energetic carbon-12, which promptly splits into a helium nucleus and a beryllium nucleus. The beryllium then splits into two more helium nuclei. The result is “three helium nuclei, each having almost three million electron volts of energy,” according to Gay, who has written a paper explaining Bussard’s research in layman’s terms.

The force of splitting flings the helium nuclei out from the center of the reactor toward an electrical grid, where their energy would force electrons to flow — electricity.

This direct conversion process is extraordinarily efficient. About 95 percent of the fission energy is turned into electricity, Gay said.

 

[Jonti]

There's a yahoo news group for folks interested in the power applications of IEC Fusion, technical talk, economics, finance R&D etc.

http://tech.groups.yahoo.com/group/IEC_Fusion/

 

[Crispy]

Nobody uses it
http://www.fusor.net/ has lively fora, and the nasaspaceflight thread moves quite quickly, for latest news.

 

[Jonti]

I think the yahoo group is supposed to be more for potential interested (very wealthy) angels. Don't suppose there's that many billionaire readers here, mind ...

Bussard is sure the science is right, and, according to the nasaspaceflight forum Crisply linked to above, is still looking for funding to take the idea forward*. Up to now, the research has been funded by the US Navy (who are naturally interested in compact power sources) but the financial demands of current military committments meant his work got taken out by a budget review. In the plus side, it means he can now talk about it.

There's a write up of that video (the Google Tech Talk seminar) available in pdf from http://www.askmar.com/Fusion.html -- there's a whole bunch of other good links on that page. And here is a page of links which attempts to be a list of web pages that give Bussard's approach to fusion anything more than a passing mention.

Interesting stuff. My personal Doomsday Clock just put itself back a second or two

* despite reports to the contrary elsewhere

 

[MikeMcc]

Supposedly non-radiative, but aren't energetic helium ions identical to alpha-radiation? Surely there will be some activation of the surrounding structure?

 

[Crispy]

Alpha gets stopped by a sheet of alu foil doesn't it?
I imagine the parts will get irradiated, yes, but this is an engineering challenge for all nuclear reactors, right?

 

[Jonti]

Yes, that's right. Fast moving helion ions ("alpha particles") are the only output from the device, along with some braking radiation.

(The braking or bremsstrahlung radiation makes the device "only" about 95% efficient in terms of useful energy from the mass/energy conversion -- assuming the fast moving helium ions can be used to directly induce electric currents or generate heat.)

95% efficient mass-to-energy conversion, with direct induction of electiricity from a cheap feedstock and no radioactive waste ...

The helium ions are heavy and hard to deflect with magnetic fields, so some of them will plough into the magnets and coils. They won't penetate very far or induce radioative isotopes to form, but they will degrade the surface to a depth of a few millimetres. The magnets may need replacing fairly regularly -- but they won't be radioactively hot for thousands of years or anything. More like a matter of days.

(according to what i've read)

 

[Balbi]

Sorry, but all I can imagine is this....

 

[Crispy]

Really? I'm thinking

 

[Balbi]

If you're not thinking that all the time, there's something wrong with you. Great Scott!

 

[Crispy]

1.21 Gigawatts!!!

 

[Crispy]

It's the implications for space travel that really get me. We're talking about an order of magnitude improvement in thrust and efficiency. It will make spaceflight as energy-cheap as airflight. No more scrimping on weight and fuel. You want to go somewhere? Burn the engine! No pissing around waiting for the right moment in the orbit to burn a piddling amount of precious hydrocarbons. Mars and back in a month.

 

[Balbi]

Not being a science bod (but appreciating big science nevertheless) I can recognise the amazing potential of the project. If it was given the funding it needed it'd put every concept of space travel established over the last sixty years completely out of commission.

Maybe NASA don't want their P45's

 

[Crispy]

NASA's primary objective is to keep 100,000's of aerospace engineers and scientists in jobs in every congressional district.

 

[Jonti]

It's the implications for space travel that really get me. We're talking about an order of magnitude improvement in thrust and efficiency. It will make spaceflight as energy-cheap as airflight. No more scrimping on weight and fuel. You want to go somewhere? Burn the engine! No pissing around waiting for the right moment in the orbit to burn a piddling amount of precious hydrocarbons. Mars and back in a month.

Yours and Bussard's both. And yes, the implications are startling. Bussard's design would make it possible to reach mars in weeks, rather than months or years. A colony on Titan would be possible. Exiting, but useless and irrelevant for most of us.

Thing is, we already live in space -- the task is to learn how to share and care for our existing, natural, life support systems. If we can't do that where we evolved (or where we 'belong') we far less likely to succeed in what are likely to be far more stressful and fragile artificial habitats.

So, back on Earth for a while, these are the kinds of things that a clean, compact fusion power source would make possible (according to Bussard) ...

• an end to the greenhouse effect from fossil-fuel CO2
• an end to atmospheric smog as coal plants are replaced
• an end to acid rain (for the same reasons)
• reduced thermal pollution (from the increased efficiency of power generation)
• an end to the production of lethal radioactive waste that is dangerous for thousands of years
• a way to process the waste we already have (using DT-fuelled versions of the fusor to irradiate the waste with neutrons, reducing its half life down from millenia to decades)
• affordable desalination to produce fresh water from the sea at about 2% of the current cost

It would be a different planet. And it looks as if the science is right -- all that's left is the engineering ...

 

[Crispy]

You're completely right, of course. All that boring stuff is very important
Bring me my starship!

 

[Jonti]

Me first!!

 

[Bob_the_lost]

reduced thermal pollution (from the increased efficiency of power generation)

He's very wrong on that one though.

 

[Jonti]

He's thinking of direct induction of electic current from the helium ions ...

 

[Bob_the_lost]

He's thinking of direct induction of electic current from the helium ions ...

Yeah, but while the reduction in efficency there would reduce waste heat, an ultra cheap method of producing energy will just mean people use more of it. The net result will be more thermal pollution.

 

[Crispy]

Yeah - it all turns into heat in the end - no matter the efficiency. I seem to remember A.C.Clarke speculating on a future world that cooks itself with almost unlimited fusion power at its disposal.

 

[Bob_the_lost]

Yeah - it all turns into heat in the end - no matter the efficiency. I seem to remember A.C.Clarke speculating on a future world that cooks itself with almost unlimited fusion power at its disposal.

Niven has it too with the Puppeteer worlds i think.

Still, that'd be a problem for the future, i'm just nitpicking.

 

[Jonti]

'cos it all ends up as heat eventually.

Yeah, I see what you're saying. But at least entire rivers or seas won't be have to warmed a degree or two, just to run the power stations.

In planetary terms, man's energy production is still very tiny -- it's the (poisonous) ways it's pressently done that are the problem, not its absolute magnitude as such (I think).

 

[MikeMcc]

Yeah, but while the reduction in efficency there would reduce waste heat, an ultra cheap method of producing energy will just mean people use more of it. The net result will be more thermal pollution.

I don't really think that's too much of a problem for the planet as a whole given what we have sitting just a few thousand feet beneath us!

 

[Crispy]

I don't really think that's too much of a problem for the planet as a whole given what we have sitting just a few thousand feet beneath us!

Well yes, for now it's not a problem, but when everyone has Mr.Fusion in their back garden, with their own personal rocket ship, cyclotron and element-transmutator....

 

[Crispy]

http://en.wikipedia.org/wiki/Polywell - This is the best description of the machine I can find.
http://askmar.com/ConferenceNotes/Should Google Go Nuclear.pdf - and this is Bussards paper that went with the google talk - has a good summary and a Q&A section at the back.