polywell fusion (was Re: Russia to build factories on Moon?)

In article <m869239jb1ichcekgtvkcgit27pukdi06n@xxxxxxx>,
John Schilling <schillin@xxxxxxxxxxxxx> wrote:

The real reason it seems bogus to me is that there is very little market
for He-3, and I doubt there ever will be. (When polywell reactors come
on line, they'll be burning protons and boron, not He-3.)

Heavy polywater would seem a more suitable fuel :-)

You jest. But have you actually looked into it?

Yes, I have. I've also looked into Todd Rider's work on nonequilibrium
fusion in general, and I find his arguments a *lot* more convincing than
the vague, handwaving denials of Bussard's supporters. To the best of
my knowledge, Bussard himself has never addressed the issue - despite
the fact that he should have discovered it before Rider himself.

You should go by something other than the vague handwaving of Bussard's
supporters then. Like, for example, Bussard's 1991 Fusion Technology
paper, where he addresses the issue (if you're referring to
Bremsstrahlung losses) in detail in section IV.C:

http://www.strout.net/info/science/polywell/bussard-1991.html

These effects are important in that they determine the minimum well
depth needed for a particular fuel, but they are not a major obstacle.

Note too that in 1995 (when Rider published his thesis), it was not yet
known how to recycle electrons lost through the cusps in the magnetic
field. Those electrons were simply gone, as were electrons spiraling
along field lines that intersected metal (i.e. the magnet coils and
their support structure). WB-1 in 1994 got recirculating electrons, but
still had field lines intersecting structure. It wasn't until WB-6 in
2005 that this latter problem was solved (showing 1/10 the loss
coefficient of WB-4, the previous best recirculating machine).

Also, according to Bussard's notes, it was WB-2 (1994-96) that developed
the "first empirical transport scaling electron loss formulae." But this
was all under embargo; Rider couldn't have seen it, so I don't know how
he could possibly calculate the scaling of electron loss, even if he'd
been working with the correct (non-intersecting) field geometry.

I'm sure Rider's results are important and deserve careful study, but it
would surprise me if he was able to make predictions based solely on
theory better than what Bussard can do with his combination of theory
and hands-on experimental results.

OK, now convince me. Start by specifying the actual temperature and
pressure at which H1-B11 fusion will produce fusion power exceeding
the bremsstrahlung losses. Or, if you prefer, the actual electron
and ion energy distribution functions.

How about I share the relevant papers instead? I've tried to list them
all at <http://www.strout.net/info/science/polywell/>, but if you can't
be troubled to get them yourself, I can lend you my copies.

Also, pop some corn and sit down for Bussard's lecture at Google some
evening. You clearly have enough physics background to follow most of
what he says, and I bet you'll find it very intriguing. He shows
results (yes, crudely -- the graphs are from internal Navy reports)
which have not yet been published, but should still not be ignored.

Best,
- Joe
.

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