First amateur polywell fusion reactor, in a Brooklyn apt | Hacker News Reader

First amateur polywell fusion reactor, in a Brooklyn apt

prometheusfusionperfection.com

75 pointsjoewadcan32 comments

There was no actual fusion reaction occurring in this test. He just confined electrons in an air plasma. No hydrogen was injected.

And, of course, it didn't take place in an apartment.

well, starting from 20-30KV the plasma may start radiating X-rays (bremsstrahlung).

Nitpick: It's not an apartment, it's a shared lab space near the Marcy Projects. I visited a while back and it was cool.

Awesome work, Mark!

Haha, I interviewed this guy for a position a while ago and saw his reactor and workshop. It's totally boss but it wasn't in an apartment but rather in a huge warehouse workshop space.

what are the implications of this?

fusion funds, energyscript, claims that lisp is better than fusion.

schemaless fusion, lots of advice about "how I got fusion."

"Top 10 reasons your fusion is not reaching customers."

Aww, HN takes itself so seriously...

well of course, they're changing the world one daily deal at a time. what has nuclear engineering ever done for society?

Certainly not as much as Groupon

you forgot your </sarcasm>

We just don't want it to turn into reddit.

Cannot upvote enough.

That part of HN is already worse than Reddit, though.

Yeah, injecting a little humor into the discussion around here would really ruin the place.

Edited to add: may you dour bastards choke on something.

This made my day, thanks. :)

My thoughts on it: you can find humor anywhere on the internet. It's much harder to find decent discussion. When humor and decent discussion try to coexist, humor tends to crowd out the discussion.

Why bother posting detailed information about what kind of reaction is going on when you can make a simple joke about nuclear power and get as much karma? Why bother posting something intelligent when it will be buried below puns?

I used to think HN downvoting humor was bad, but I've really come to agree with it after looking at some attempts at serious discussion on reddit. Without fail, by the third comment or so, someone will derail it with a predictable joke or pun. Humor is easy. Interesting comments are not.

fusion on rails. VCs telling 22 year-olds that they are changing the world - one electron at a time.

None. It's just a cool amateur electronics project. Energy in >> energy out.

In fact, I'm assuming and hoping for the sake of his neighbours that he's not actually attempting fusion. If I recall correctly, doing actual fusion with one of these requires deuterium and tritium and produces a crapload of neutrons for which I really doubt he has adequate shielding.

I'm pretty sure the experiment which he's attempting to replicate was never done with deuterium-tritium either, for similar reasons.

I'm not sure about this one, but I know polywell reactors can be hot enough to use deuterium-deuterium reactions. It's cheaper, easier to extract energy from, and leaves stable helium nuclei with no stray neutrons.

Nope.

D-D fusion produces a 2.54 MeV neutron 50% of the time.

  In fact, I'm assuming and hoping for the sake of his neighbours that 
  he's not actually attempting fusion. If I recall correctly, doing 
  actual fusion with one of these requires deuterium and tritium and 
  produces a crapload of neutrons for which I really doubt he has 
  adequate shielding.

Yes and no.

The very lowest-energy-threshold fusion reaction is deuterium-tritium, so must research tokamak reactors use that. The JET[1], ITER[2], et al.

But tritium is both expensive and excitingly dangerous, (It's an alpha emitter, which is ordinarily harmless, since the alpha particles aren't energetic enough to penetrate skin; but it's a radioactive gas, not a solid, so you can inhale it and get all sorts of amusing cancers) so real amateurs prefer Deuterium-Deuterium fusion, and the kind of fusion reactor that that produce the higher energies needed to accomplish it, known as fusors[3].

D-D fusion does produce neutrons, you are correct. But the PF reactor is a pulsed device, with a tiny coil size: it doesn't make many neutrons, and it produces them for seconds at a time. This guy has been checked out by the NYFD, and they've signed off on the project. If it was a power reactor, neutron emission would be a problem, but it's not, so it ain't.

1: http://en.wikipedia.org/wiki/Joint_European_Torus 2: http://en.wikipedia.org/wiki/ITER 3: http://en.wikipedia.org/wiki/Fusor

tritium is both expensive and excitingly dangerous, (It's an alpha emitter...

Err... you sure about that? Must be some interesting physics going on for a p-n-n to emit a p-p-n-n. ;-)

I'm guessing you meant beta emitter?

Whoops! You are correct.

This guy has been checked out by the NYFD

Well, OK then. Important safety tip: Don't cross the streams.

To be remembered down through the ages as the Great Vaporization of Brooklyn, August 3rd, 2011.

Nope.

Fusion reactors are fundamentally different from fission reactors. You have to get a tenuous wisp of hydrogen (the reactor in this particular experiment was running at 10 mTorr, or 0.0013% atmospheric pressure) very, very hot, and keep it away from solid matter, which is millions of degrees of colder than the fuel plasma, and will suck all of the energy out of the reaction.

You shut off the containment coils, and tremendously hot plasma ions leap away from each other, instantly stopping the reaction. If the reaction somehow "runs away", which it absolutely can't, then it brushes the walls of the vacuum chamber, poisoning it with cold metal ions, like injecting lead shavings that have been chilled to absolute zero directly into your heart.

If our magical "runaway reaction" somehow overcomes this, and melts a hole in the vacuum chamber, then the atmosphere rushes in, both freezing cold and at intolerably high pressure, like the North Sea flooding into the hull of a submarine resting on the ocean floor.

Fusion reactors don't melt down, or explode. At all. It just can't happen, much like how a Yugo rear-ending a garbage truck in Brooklyn doesn't instantly consume all of New York City in a gasoline fireball.

It is indicative of the great difficulty of both starting and sustaining a fusion reaction that the only fusion reactions which produced more energy than they consumed, that have ever taken place on Earth were powered by atomic bombs, and still only ran for fractions of a second.

Way to inject lead shavings that have been chilled to absolute zero directly into the best joke I've heard today :)

It's worth calling out that a cubic meter of the sun's fusion reaction generates about the same power as an active compost heap. http://en.wikipedia.org/wiki/Sun#Core - the huge energy output is due to the huge volume

Thankyou, I have a new favourite fun fact.

That really surprised me until I looked it up, and read in Wikipedia that "At the center of the Sun, theoretical models estimate it to be approximately 276.5 watts/m3, a power production density that more nearly approximates reptile metabolism than a thermonuclear bomb" and realized a few seconds later that an object with a thermonuclear bomb's power generation density, the size of the Sun, would not look like a thumb-sized blazing ball of fire from 93 million miles away. It would look like a supernova, and explode around as fast.

The Soviet Tsar Bomb had a power output of 5.4 yottawatts - apparently about 1% of solar power output.

Of course, this was for a pretty short time, 39 nanoseconds, but it is still rather impressive.

http://digg.com/news/story/The_Most_Powerful_Device_Ever_Uti...

Reply on news.ycombinator.com