The lost nuclear fusion reactor design?

Watts Up With That? ^ | March 31, 2015 | By Eric Worrall

[Brad from Tennessee]

Not many people have heard of Robert Bussard, but he was one of the giants of nuclear fusion research. But if an engineering solution for viable small, household size nuclear fusion reactors is ever discovered, they will almost certainly be largely based on Bussard’s work.

Bussard’s focus was on a field of Nuclear fusion research known as electrostatic confinement. Unlike the better known magnetic bottle reactors, such as the $20 billion ITER project, electrostatic confinement can be applied to fusion plasmas which are the size of a small glass fish tank.

Electrostatic confinement has been well known since the 1930s. Small electrostatic nuclear fusion devices are sold commercially – as neutron sources. A small nuclear fusion reactor is an incredibly convenient way to produce a dense stream of neutron radiation, because as soon as you switch off the power, the plasma cools, and the radiation stops.

The problem is nobody has figured out how to extract more energy out of an electrostatic fusor, than you put into it. . .

[tanknetter]

“Not many people have heard of Robert Bussard”?

Um, besides anyone familiar with why the red domes on the front of most Starfleet ships’ warp nacelles from Star Trek happen to be called “Bussard Collectors”???

[Lx]

Wait, I’m missing something. If you’re fusing two atoms before iron on the periodic table, Don’t you release energy equal to e=mc2? No violation of the first law unless it takes more energy to fuse them then you get???

I’ve read your stuff before and I know you’re not an idiot so what am I missing?

[Olog-hai]

It’s not what I wrote, but what they wrote in the article in the OP.

I’d say they’d use the same language with reference to burning coal; since the only thing done to extract the energy from the coal is using a low-energy (relative to the size of the coal) flame to ignite it, they’d call it getting more energy out than putting in.

[mad_as_he$$]

Winner!

[DiogenesLamp]

And of course, a form of hot fusion.

In context, that term is very misleading. It has been the source of many arguments on the talkpolywell website due to the fact that a man named "Rider" published a peer reviewed document that is regarded as proving such devices are unworkable because the plasma will thermalize.

Dr. Bussard contends that the plasma won't thermalize (become a chaotic mess of atoms bouncing around on each other) but will instead maintain a relatively ordered steady state condition.

His design incorporates the same concept as that of a star. Gravity pulls matter together into the center of a star, and it also holds together this superhot mass of matter at sufficient temperatures and pressures to fuse.

Dr Bussard (and Farnsworth before him) decided that electrostatic fields could serve the same purpose as that of gravity, but because electrostatic fields are many thousands of times stronger than gravity, the devices could be much smaller than a star.

Farnsworth used a spherical grid in the center of his device, but the design was inefficient because the physical grid kept getting hit by high energy particles. In normal operation, the grid gets so hot that it starts to glow red.

Bussard's idea was to eliminate a physical grid and create a "virtual grid" out of trapped electrons. He confines electrons in the center of a several overlapping magnetic fields, and then he uses that very powerful negative charge to perform the task that gravity would in a star.

He allows Ions to fall toward's this "well" and they gain velocity as they fall. By the time they reach the center, they have enough velocity to fuse if they hit an Ion traveling in the opposite direction at the same velocity.

If the dropped Ion doesn't hit another ion in the center, it continues on it's path, but this time losing velocity until it once again reaches the edge of the well, but on the opposite side. It then proceeds to reverse direction, and start falling back into the center of the well, where it will eventually hit an Ion traveling in the opposite direction but of equal velocity.

Imagine a three Dimensional frictionless half pipe with trillions of balls rolling back and forth until they hit one another at the bottom and fuse.

Dr Bussard calculated that each Ion might undergo 10,000 oscillations past the center of the well before they finally hit another Ion hard enough to fuse, but by 10,000 oscillations fusion was a virtual certainty.

[Resolute Conservative]

E = mc^2

[Elderberry]

E²=(mc²)²+(pc)²

[Lx]

So they don’t know the difference between a chemical VS nuclear reaction?

[Some Fat Guy in L.A.]

Also the Bussard Ramjet from Larry Niven’s stories.

[Colinsky]

I thought the consensus was that Thorium Molten Salt Reactors were the way to go?

One reason that thorium reactors were deprecated is that they didn't produce plutonium as part of the nuclear reaction path. Governments wanted the plutonium.

[CurlyDave]

Also the Bussard Ramjet from Larry Niven’s stories.

Actually, Bussard proposed the ramjet, Larry Niven just brought the idea to the attention of the public.