Boron Fixed Target

Discuss how polywell fusion works; share theoretical questions and answers.

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wolfspelz
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Joined: Thu Jan 21, 2010 7:14 pm

Boron Fixed Target

Post by wolfspelz »

Hi, noob question:

If we want to fuse P + B11. Why don't we just accelerate protons with 600 keV on a solid B11 target?

clonan
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Joined: Tue Jun 10, 2008 4:16 pm

Post by clonan »

I asked the same question...

viewtopic.php?t=800&highlight=

TallDave
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Post by TallDave »

The short answer is: because beam-target fusion doesn't scale very well. You can get fusion that way, but not enough to make net power.
n*kBolt*Te = B**2/(2*mu0) and B^.25 loss scaling? Or not so much? Hopefully we'll know soon...

Art Carlson
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Location: Munich, Germany

Re: Boron Fixed Target

Post by Art Carlson »

wolfspelz wrote:If we want to fuse P + B11. Why don't we just accelerate protons with 600 keV on a solid B11 target?
Indeed, if your goal is producing p-B11 fusion reactions, that is the easiest way to do so. However, some of us here are also interested in producing net power from fusion reactions.

chrismb
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Post by chrismb »

TallDave wrote:The short answer is: because beam-target fusion doesn't scale very well. You can get fusion that way, but not enough to make net power.
No idea what you mean by 'scales easily'. A beam-target device scales perfectly, and linearly!

The issue is that the cross-section for scattering is >> cross-section for fusion. What that means is that for a billion billion protons that head towards the target, you'll be lucky to get one that fuses. The vast majority just get slowed by all the electrons in the target, which heats it, and those tiny few that get past the electrons and actually head up towards a nucleus simply bounce away.

Fusion is like buying a lottery ticket - but just much much less likely!!! It;s not like burning a gas in air. In combustion the molecules will bounce around until they *do* burn. In fusion, they bounce around and loose all their energy.

So, sure you can do that and you get fusion. But you'll get so little fusion it'd be virtually undetectable.

Works quite well for DT type beam-target arrangements.

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