Polywell in fiction
Polywell in fiction
I know that Joe Strout has noted that author Karl Schroeder has mentioned polywell on his site in the past, but I just came upon his mentioning it in a short story of his called The Hero. The setting is his Virga universe of which I've only read the first book and this short story. It's the first mention of a polywell in fiction that I've seen. Anybody know of any others out there?
Ahem.
"El Dorado", October 2007 Analog Science Fiction and Fact. By some guy named Tom Ligon. It featured ships derived from Dr. Bussard's designs, specifically with Polywell power sources.
He lived to see the article in print, a couple of months before he passed. I was able to get a little input from him on the weapon the ships were up against, an interstellar ramjet starkiller of his design. I told him I'd put his best invention up against his worst invention.
The sequel, "Payback", appeared in July-August 2009. It does not mention the Polywell, but the economy largely runs on them.
I need to read Karl's though. We both seem to have gone for the hero theme. Mine was reasonably well regarded, but his made a Year's Best anthology.
"El Dorado", October 2007 Analog Science Fiction and Fact. By some guy named Tom Ligon. It featured ships derived from Dr. Bussard's designs, specifically with Polywell power sources.
He lived to see the article in print, a couple of months before he passed. I was able to get a little input from him on the weapon the ships were up against, an interstellar ramjet starkiller of his design. I told him I'd put his best invention up against his worst invention.
The sequel, "Payback", appeared in July-August 2009. It does not mention the Polywell, but the economy largely runs on them.
I need to read Karl's though. We both seem to have gone for the hero theme. Mine was reasonably well regarded, but his made a Year's Best anthology.
I'm using the Polywell in a story I'm writing, though I haven't specifically mentioned it yet., though I have mentioned one of its effects ($2/kg to L4! (that includes pilot's pay, airport fees, etc)).
However, one problem I have: how much bigger than the magrid does the shielding have to be? (ie, how much space between the grid and the walls of the chamber?). In my designs, I've got only a few 10s of centimeters (for a 2m radius grid (and also a 4.5m radius)), for the sake of reducing the mass (tungsten is viciously heavy: about 1/2 the ships' mass is shielding!
However, one problem I have: how much bigger than the magrid does the shielding have to be? (ie, how much space between the grid and the walls of the chamber?). In my designs, I've got only a few 10s of centimeters (for a 2m radius grid (and also a 4.5m radius)), for the sake of reducing the mass (tungsten is viciously heavy: about 1/2 the ships' mass is shielding!
Regarding the density of tungsten, I just came from the fusor.org forum, where somebody announced a source of tungsten ... you can buy fishing weights made from it from Bass Pro Shops!
Its an interesting challenge. You can use low-z shields when working with high-energy electrons and charged particles, but bremsstrahlung is going to be hard to beat without serious mass. For ground to LEO I think you may not try to shield the reactor, but shield the crew and passengers instead. The flight should be quick, so put the people into the smallest, longest cylinder you can, something like an airliner fuselage, and shield the back.
For deep space, our health physics professor told us the best shielding is the inverse square law. Put the crew compartment on a long boom. At some distance the non-trivial radiation of space becomes more of a worry, so you shield to that and you're done.
Its an interesting challenge. You can use low-z shields when working with high-energy electrons and charged particles, but bremsstrahlung is going to be hard to beat without serious mass. For ground to LEO I think you may not try to shield the reactor, but shield the crew and passengers instead. The flight should be quick, so put the people into the smallest, longest cylinder you can, something like an airliner fuselage, and shield the back.
For deep space, our health physics professor told us the best shielding is the inverse square law. Put the crew compartment on a long boom. At some distance the non-trivial radiation of space becomes more of a worry, so you shield to that and you're done.
"Gamma-Ray Interactions with Matter"
http://library.sciencemadness.org/lanl1 ... 326397.pdf
http://library.sciencemadness.org/lanl1 ... 326397.pdf
Table 2-2 shows that at energies above 500 keV the tungsten alloy has a significantly
higher linear attenuation coefficient than lead because of its higher density. Thus,
the same shielding effect can be achieved with a thinner shield. At energies below
500 keV, the difference between the attenuation properties of the two materials is
less significant; the higher density of the tungsten alloy is offset by the lower atomic
number. The tungsten alloy is used where space is severely limited or where machinability
and mechanical strength are important. However, the tungsten material is over
thirty times more expensive than lead therefore, it is used sparingly and is almost
never used for massive shields. The alloy is often used to hold intense gamma-ray
transmission sources or to collimate gamma-ray detectors.
Table 2-2. Attenuation properties of lead and tungsten
...........................Attenuation Coefficient (cm-1).....Thickness (cm)*
____________________________________________________________
Energy (keV)........Lead...Tungsten**.......................Lead....Tungsten**
1000....................0.77....1.08.................................2.98.....2.14
500......................1.70....2.14.................................1.35.....1.08
200......................10.6....11.5.................................0.22.....0.20
100 .....................60.4....64.8.................................0.038...0.036
* Thickness of absorber with 10% transmission.
** Alloy: 90% tungsten, 6% nickel, 4% copper.
Shielding discussed further at
viewtopic.php?t=2022
viewtopic.php?t=2022
If Homeland Security comes, drop my name and I'll put in a good word for you.
I consult for them, they know I'm active with fusors and the Polywell, and I've never heard a bit of concern from them on the issue.
Buying deuterium probably does get your name on a list, but I remember having to sign for methanol when I bought it years ago because it is listed as a poison.
I recently visited a website that sells photoflash capacitors and other high performance caps, needing one for a spot welder I'm building. One mid-sized cap they sell can store 500 joules, and they point out that ten of these in parallel store 5000 joules, and say it could make a sporty rail gun. They also point out that the muzzle energy of a 30-06 round is about 750 joules. Now that oughta get you on a list!
I consult for them, they know I'm active with fusors and the Polywell, and I've never heard a bit of concern from them on the issue.
Buying deuterium probably does get your name on a list, but I remember having to sign for methanol when I bought it years ago because it is listed as a poison.
I recently visited a website that sells photoflash capacitors and other high performance caps, needing one for a spot welder I'm building. One mid-sized cap they sell can store 500 joules, and they point out that ten of these in parallel store 5000 joules, and say it could make a sporty rail gun. They also point out that the muzzle energy of a 30-06 round is about 750 joules. Now that oughta get you on a list!
I'm sure fusor.net is watched. This one is, too, I'm pretty sure. I'm also sure they realize there is nothing subversive or dangerous going on in either. I've seen fusor.net discourage and chase off people with an irresponsible or suspicious attitude.
Thiago Olsen, as a high school student working on a fusor, was indeed visited by the nuclear safety officials in his state. They concluded his apparatus would produce safe levels of radiation, and that in fact he had done his homework, knew the hazards, and was taking proper precautions. They blessed his project and went on their way.
Richard Hull's uranium fascination is due to an old hobby of his, collecting the elements. He is only interested in common mineral forms. But how many rock hounds do you know who have scrounged up a gamma ray spectrometer, and know how to calibrate it using a smoke detector? The thing is, with the gamma spec, he can check off a number of rare and fleeting elements off his list, in one rock.
I can't be certain, but I suspect Talk-Polywell.org has influenced public policy, especially funding on small and innovative fusion policy. It does that because of the high quality of discussion that goes on here. Fusor.net has the same characteristic.
Like radio amateurs joining the armed services during wartime, I expect any successful fusion program will tap this talent pool. That's why Dr. Bussard had me write an article suggesting fusors be built as amateur science projects.
Getting back to the original topic, there was a fictional companion piece to the original Analog fusor article. It was rejected, and has never been published. If has Polywell rockets based on Dr. Bussard's proposed designs, from the aerospace plane up to the Mars craft.
Thiago Olsen, as a high school student working on a fusor, was indeed visited by the nuclear safety officials in his state. They concluded his apparatus would produce safe levels of radiation, and that in fact he had done his homework, knew the hazards, and was taking proper precautions. They blessed his project and went on their way.
Richard Hull's uranium fascination is due to an old hobby of his, collecting the elements. He is only interested in common mineral forms. But how many rock hounds do you know who have scrounged up a gamma ray spectrometer, and know how to calibrate it using a smoke detector? The thing is, with the gamma spec, he can check off a number of rare and fleeting elements off his list, in one rock.
I can't be certain, but I suspect Talk-Polywell.org has influenced public policy, especially funding on small and innovative fusion policy. It does that because of the high quality of discussion that goes on here. Fusor.net has the same characteristic.
Like radio amateurs joining the armed services during wartime, I expect any successful fusion program will tap this talent pool. That's why Dr. Bussard had me write an article suggesting fusors be built as amateur science projects.
Getting back to the original topic, there was a fictional companion piece to the original Analog fusor article. It was rejected, and has never been published. If has Polywell rockets based on Dr. Bussard's proposed designs, from the aerospace plane up to the Mars craft.
I have made myself rather a pest on the I'net evangelizing Polywell. I still do that some. I'm so "bad" that there are blog posts out there complaining of my ubiquity. No doubt I'm on a list - if there is one. So far the Men In Black have left me alone. And I have had run ins with them in a past life so there is a good chance I would recognize the signs.
In any case I'm too old to worry about that sort of thing.
If I was going to worry about anything it would be the DEA. I have been an effective enemy of theirs for years. So far nothing. (Well I hope I'm not tempting fate here).
In any case I'm too old to worry about that sort of thing.
If I was going to worry about anything it would be the DEA. I have been an effective enemy of theirs for years. So far nothing. (Well I hope I'm not tempting fate here).
Engineering is the art of making what you want from what you can get at a profit.
This board is about nuclear technology in general and one application in particular. Orions (nuclear bombs need must apply) are an intermittent topic of conversation, amusement and practical contemplation (i.e. how to build them).MSimon wrote:I have made myself rather a pest on the I'net evangelizing Polywell. I still do that some. I'm so "bad" that there are blog posts out there complaining of my ubiquity. No doubt I'm on a list - if there is one. So far the Men In Black have left me alone. And I have had run ins with them in a past life so there is a good chance I would recognize the signs.
In any case I'm too old to worry about that sort of thing.
I would be very surprised if every member of and multiple visitor to T-P has not been logged to a set of pattern-recognition watch lists at Fort Meade. I know for a fact that a political list I belong to has made it to a DoS watch list.
Vae Victis