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09-06-2017, 10:35 AM | #1 |
Join Date: May 2010
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[Ultra-Tech] [Spaceships] Weapons that are hard or impossible to miniaturize
In Transhuman Space, particle beams have a minimum size that allows them to be installed on SDVs but not smaller ships. (SDVs are typically SM +10 or +11, though Spaceships 8 mentions particle beams can be installed on ships as small as SM +8.) Spaceships 7 has an optional rule to put similar limits on X-ray lasers, antiparticle beams, and grasers. Some questions about this:
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09-06-2017, 10:52 AM | #2 | ||
Join Date: Feb 2005
Location: Berkeley, CA
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Re: [Ultra-Tech] [Spaceships] Weapons that are hard or impossible to miniaturize
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No, except maybe by coincidence. |
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09-06-2017, 02:41 PM | #3 | ||||
Join Date: May 2010
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Re: [Ultra-Tech] [Spaceships] Weapons that are hard or impossible to miniaturize
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09-06-2017, 02:47 PM | #4 | ||
Join Date: Feb 2005
Location: Berkeley, CA
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Re: [Ultra-Tech] [Spaceships] Weapons that are hard or impossible to miniaturize
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I'd probably go with -2 per TL. |
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09-06-2017, 05:01 PM | #5 |
Join Date: May 2010
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Re: [Ultra-Tech] [Spaceships] Weapons that are hard or impossible to miniaturize
Reading up on FELs, it looks like wavelength is inversely proportional to particle energy. Therefore would 1/10x wavelength require 10x the length? That would make FEL grasers limited to truly massive installations, even moreso than x-ray lasers, right?
Last edited by Michael Thayne; 09-06-2017 at 08:32 PM. Reason: said "10x" when I meant "1/10x" |
09-06-2017, 05:07 PM | #6 |
Join Date: Feb 2005
Location: Berkeley, CA
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Re: [Ultra-Tech] [Spaceships] Weapons that are hard or impossible to miniaturize
Presumably there's tech improvements if they're making them as weapons at all, but yes, you'd expect a FEL at gamma wavelengths to be larger than an X-ray installation.
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09-06-2017, 02:18 PM | #7 | |
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Join Date: Sep 2004
Location: Southeast NC
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Re: [Ultra-Tech] [Spaceships] Weapons that are hard or impossible to miniaturize
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RyanW - Actually one normal sized guy in three tiny trenchcoats. |
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09-06-2017, 09:34 PM | #8 | ||||
Join Date: Nov 2004
Location: The plutonium rich regions of Washington State
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Re: [Ultra-Tech] [Spaceships] Weapons that are hard or impossible to miniaturize
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https://en.wikipedia.org/wiki/Plasma_acceleration We're still working out some of the kinks at TL 8 - we can get particle energies of a GeV in a few cm, but the emittance may not be tight enough to be usable as a spacecraft-to-spacecraft weapon. Also, the theoretical maximum amount of energy you can transfer from your laser pulse to a particle bunch is 50%, in practice current wakefield accelerators are more like 10% to 20%. At this point you need to ask yourself if you should just use that laser to fry your enemies instead. If you use the particle beam from a wakefield accelerator to drive an x-ray free electron laser, you can get around the emittance problems - FELs self-organize their electron bunches to draw energy from the particles and transfer it to the x-ray field. Quote:
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We don't have gamma ray lasers, but you can use particle beams to get narrow gamma ray beams using laser Compton backscatter (in principle, you can also use positron annihilation in flight, but that's a tech path that we are not currently pursuing in favor of Compton backscatter). Quote:
https://en.wikipedia.org/wiki/Halbach_array This forces the electrons to move in a sinusoidal pattern. The modes of the electromagnetic field whose force is constantly opposing the motion of the electrons will have work done on them and be amplified. With a suitably long wiggler or a resonant cavity, you can get a very narrow band of modes, like a laser beam. If the radiation field is intense enough and the wiggler is long enough, the electrons will self-organize into bunches to produce super-radiant coherent motion. Now you have a free electron laser. For a tuneable FEL, you will need separate wigglers for different frequency bands. The wiggler for the x-rays will have a pitch way too short for when you need visible light, so you would divert the electron bunches to a visible light wiggler. (The visible light wiggler would probably also be inside a Fabry-Perot resonant cavity, https://en.wikipedia.org/wiki/Fabry%...interferometer allowing you to achieve your laser behavior threshold with a much shorter wiggler.) Luke |
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09-07-2017, 09:47 AM | #9 | ||
Join Date: May 2010
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Re: [Ultra-Tech] [Spaceships] Weapons that are hard or impossible to miniaturize
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09-07-2017, 08:07 PM | #10 | |||||
Join Date: Nov 2004
Location: The plutonium rich regions of Washington State
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Re: [Ultra-Tech] [Spaceships] Weapons that are hard or impossible to miniaturize
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Luke |
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