Transterrestrial Musings

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It was cancer. I spent a morning with him this past spring as he was about to undergo some specialized radiation therapy. He was weak but in good spirits and raring to go on Polywell fusion if funds could be found.

He was a classic, and I'm very sad to see such an innovator go. Like Max Hunter, he came from a different age, and we won't see his like again.

Gary C Hudson

Posted by at October 8, 2007 04:46 PM

That is truly a loss for us all. Dr. Bussard was one of my hero's and inspirations as a child.

Posted by Dennis Ray Wingo at October 8, 2007 06:47 PM

He will be sadly missed.

I feel like I have lost my closest fried and yet he and I never met.

Warp speed Dr. B.

http://powerandcontrol.bl*gsp*t.com/2007/10/dr-robert-w-bussard-has-passed.html

Posted by M. Simon at October 8, 2007 08:16 PM

It is a great loss. I agree with M.Simon: "Warp Speed, Mr. B."

In answer to the headline question, probably Brice Cassenti.

Posted by jrandomamerican at October 9, 2007 05:36 AM

Man I just corresponded with him a few weeks ago!

I was working on 2 papers on applications of his reactors for space and submarines, so I sent him a couple queries on point, as I had previously over the years. The guy was always bright, friendly, generous, and open. Never was to busy to answer one of my questions, and very apologetic if he didn’t get back in a timely manor.

Here was a guy who was quietly revolutionizing industrial civilization, and I never heard of him giving attitude to anyone. Very stark contrast to other folks I’ve delt with who had far greater reason for modesty.

This is a really great loss of a great man.

Posted by Kelly Starks at October 9, 2007 07:09 AM

Here was a guy who was quietly revolutionizing industrial civilization

Uh huh.

Look, I don't want this to be interpreted as speaking ill of the dead, but from where I sit, Polywell looks like a concept that can't work, for basic physics reasons. Experimental results to date are an extremely thin reed on which to hang the breathless boosterism, with fusion power only achieved for a very short period (and that likely just from beam-background gas collisions, and with Q much less than 1), and still many (11?) orders of magnitude away from that 100 MW extrapolation.

Posted by Paul Dietz at October 9, 2007 08:49 AM

Bussard was ill for some time. I spoke to him a few months ago, when he was on a radio show.

Hopefully his dream, Polywell fusion, will continue.

http://www.talk-polywell.org/bb/index.php

Posted by TallDave at October 9, 2007 08:50 AM

Paul,

As Ligon has noted, Polywell achieved fusion at 5 Kev, and copious fusion at 12 Kev. The WB models were of course never intended to achieve Q=1, and Bussard's scaling seems reasonable. Polywell may not pan out for a variety of reasons, but it's certainly more a promising path to commercial fusion power than tokamak fusion.

We'll know more soon, with Bussard's work now funded again, WB-7 apparently being built, and the Navy reportedly on board for the $200M 100MW full-scale reactor if the test results pan out.

Posted by TallDave at October 9, 2007 08:59 AM

This is very sad. I used Bussard's book on nuclear thermal propulsion as a starting point for my calculations on microwave thermal propulsion.

Posted by Kevin Parkin at October 9, 2007 09:38 AM

I knew Bob for about 40 years. We collaborated on several fusion matters and talked often about space propulsion. I always liked him for his open attitudes and deep technical insight. He was still as sharp a a pin into old age. He was a real charmer too! He had a big impact and will be missed.

Posted by James Benford at October 9, 2007 09:46 AM

"Look, I don't want this to be interpreted as speaking ill of the dead,"

Then don't, as you have.

"but from where I sit, Polywell looks like a concept that can't work, for basic physics reasons."

I've followed your screeds declaiming the Polywell concept across four forums (I keep on thinking I'll learn something new, I've finally figured out you won't be a part of that). Your questions are answered in the positive with respect to the Polywell concept, to the extent the state of the art permits them to be answered--hence the need for the experimentation and engineering the Polywell development represents--and then you vanish to snipe with stale ammunition from some other point.

Please vanish altogether or discover some well accepted, peer-reviewed, experimentally confirmed objection to the Polywell.

To inveigh that Bussard would miss "basic physics reasons" after being at the top of the field for 40 years, and so obviously so that no further work should be done on the concept, that is speaking ill of the dead.

So please come up with new material or stop.

Yours, Tom Perkins

Posted by at October 9, 2007 09:55 AM

"Look, I don't want this to be interpreted as speaking ill of the dead,"

Then don't, as you have.

"but from where I sit, Polywell looks like a concept that can't work, for basic physics reasons."

Please vanish altogether or discover some well accepted, peer-reviewed, experimentally confirmed objection to the Polywell.

So please come up with new material or stop.

Yours, Tom Perkins

Posted by Tom Perkins at October 9, 2007 09:55 AM

As Ligon has noted, Polywell achieved fusion at 5 Kev, and copious fusion at 12 Kev.

So what? Shoot deuterons of that energy into deuterium gas and you will get fusion reactions. This has been done since the 1930s. It's easy. You can do it in your basement (there were old Amateur Scientist columns in Scientific American on building your own neutron generator using just this reaction). It lends no support to idea that the Polywell concept is workable.

Bussard's scaling seems reasonable.

I strongly disagree. The scaling is a wild extrapolation, over a factor of 100 billion or so in fusion power, and given that they don't even seem to have evidence that the handful of neutrons they saw came from beam-beam collisions rather than beam-background gas collisions.

but it's certainly more a promising path to commercial fusion power than tokamak fusion.

With H-11B fuel in the Polywell, I disagree, since I don't think it can work at all.

Posted by Paul Dietz at October 9, 2007 09:59 AM

Oh I missed this:

Please vanish altogether or discover some well accepted, peer-reviewed, experimentally confirmed objection to the Polywell.

This is rich. Un-peer-reviewed results from the Polywell crowd are ok, apparently, but not from critics.

In fact, the theoretical no-go results about H-11B fusion, detailing the basic physics objections, have been in the literature for a decade. Bussard et al. never published a rebuttal to those results in the peer-reviewed literature, as far as I can tell.

Posted by Paul Dietz at October 9, 2007 10:09 AM

So what?

So, no one does fusion at 5 Kev, and no one has ever produced anything like the neutron counts seen in the three 12Kev WB-7 test runs at that power. These are not Hirsh-Farnsworth numbers, and they do in fact lend tremendous support to the notion Polywell may be viable.

The scaling is a wild extrapolation,

The scaling equations aren't especially complicated or esoteric. I suppose they are "wild" in the sense that a 5th power gain as function of the radius is large, but that's just the physics of it.

Again, Polywell may not pan out for a variety of reasons. But we're spending $10B on ITER even though a net power tokamak fusion reactor, which technology is 50 years from net power and which reactors would be so large and radioactive they makes no commercial sense anyway, even if they were free instead of probably being the most expensive things ever built. So it's hard to see how Polywell could be less promising than that, unless one ignores all the experimental evidence.

Posted by TallDave at October 9, 2007 10:17 AM

Oops, got lost in a sea of clauses. s/b "But we're spending $10B+ on ITER, which technology is 50 years from producing power and which reactors would be so large and radioactive they makes no commercial sense anyway, even if they were free instead of probably being the most expensive things ever built."

http://en.wikipedia.org/wiki/ITER

Posted by TallDave at October 9, 2007 10:40 AM

Also, the test runs were on WB-6 of course, not the under-construction WB-7.

Posted by TallDave at October 9, 2007 10:45 AM

Paul,

The scaling laws are basic physics. You have read the Valencia paper in detail I presume.

Let me add that I was also privileged to have a few words with Dr. B on the Space Show. What a thrill.

Also, even if Polywell is only capable of D-D it will still mean no requirement for exotic fuels (He3) and the radiation will be on the order of what you get from a fission plant. In a Naval Fission plant (I'm Naval Nuke qualified although my quals are no longer current) the plant is cool enough so that after 10 days shut down personnel are allowed short stints in the reactor room (I think 1 hour max - but it could be as short as 1/4 hour - I do remember the survey was leisurely) so residual radiation from the reactor vessel was not too bad.

Posted by M. Simon at October 9, 2007 02:11 PM

Very sad news.

Paul Dietz,
The physics of the Polywell reactor seems complicated enough that theoretical simulations have reached the limit of usefulness and the experiments have to be done. The cost of these is so small vs the huge benefits if it works that it seems like a gamble worth taking to me.

Simply repeating ad infinitum that it can't work seems to have little value.

When it comes to opinions on this I'll take Doc Bussard's over yours or Rider's or Nevins'. Doc Bussard was under a publishing embargo for the vast majority of the time that the Rider-Nevins objections were there. Perhaps that is why there are no peer reviewed papers rebutting them. Or maybe Doc Bussard just looked at it and convinced himself they were wrong and went ahead with his work.

Posted by Mike Borgelt at October 9, 2007 02:37 PM

You can listen to Dr. Bussard and Tom Ligon talk about the Bussard Fusion Reactor on The Space Show - mp3 about 33 MegB for those of you who need to be economical with the bits.

Posted by M. Simon at October 9, 2007 02:39 PM

I totally believe that a larger diameter D-D polywell fusion device would have electrical gain. However the following is an asset and deficit: [Here was a guy who was quietly revolutionizing industrial civilization, and I never heard of him giving attitude to anyone.] Take for example 2 very successful people in recent history. Who in my mind were insane. Howard Houghs and Martin Luther King.

Posted by Mark at October 9, 2007 03:08 PM

Mark,

The very best guys have a touch of schizophrenia. They are the out of the box thinkers you need for advances. However, they tend to be somewhat delicate in some ways personality wise.

Posted by M. Simon at October 9, 2007 05:35 PM

I was just talking to my students about this very thing today. What a sad coincidence.

Posted by Golden Bear at October 9, 2007 08:08 PM

Responding to various posts:

So, no one does fusion at 5 Kev, and no one has ever produced anything like the neutron counts seen in the three 12Kev [WB-6] test runs at that power.

The results were nothing to write home about. Conventional fusion reactors get far more neutrons. Tokamaks have been getting megawatt level output. WB-6 got an estimated 1e9 neutrons/s (but for much less than a second, so the detectors actually only saw a few neutrons). This is about 1 milliwatt of fusion power.

And contrast this to existing commericial neutron generator tubes, which can produce a time averaged 100 billion fusion neutrons per second, with the rates during the pulses much higher.

WB-6 did well compared to other IEC schemes, which just shows how pathetic IEC is in general.

The scaling equations aren't especially complicated or esoteric. I suppose they are "wild" in the sense that a 5th power gain as function of the radius is large, but that's just the physics of it.

No, a scaling by 11 orders of magnitude is wild. Period. Especially (as in this case) when the physics is unsupported by detailed experimental confirmation. The scaling law is more of an aspiration than a demonstrated reality.

Your questions are answered in the positive with respect to the Polywell concept

A gross misrepresentation. I was given fuzzy answers that failed to address the criticisms. Some of these answers, for example, seemed to contradict the second law of thermodynamics (the annealing out of the ion energy distribution, for example). That conversation eventually ended in a 'well, we'll have to see in the experiments' kind of comment from the advocates. Hardly convincing! Loss of energy of ions to electron drag in the interaction region hasn't been addressed.

When it comes to opinions on this I'll take Doc Bussard's over yours or Rider's or Nevins'.

Rider and Nevins published in the peer reviewed literature. Where did Bussards rebuttal appear in the peer reviewed literature? If it didn't, consider what an impact such a rebuttal would have had on the ease of fund raising, and ask yourself why it isn't there.

Simply repeating ad infinitum that it can't work seems to have little value.

I'll keep repeating it until the advocates justify their assertions, perferably with references to peer reviewed papers. If you prefer ignorance, I give you permission to cease reading. Given that the vast majority of Polywell material out on blogs is nearly content-free kool-aid-drinking boosterism, I think you do protest too much.

Posted by Paul Dietz at October 10, 2007 06:18 AM

The results were nothing to write home about.

In fact they were. This was 100,000 times the comparable Hirsh-Farnsworth results at similar power levels.

And contrast this to existing commericial neutron generator tubes, which can produce a time averaged 100 billion fusion neutrons per second, with the rates during the pulses much higher.

LOL You're going to compare IEC to a beam-target setup? Seriously?

No, a scaling by 11 orders of magnitude is wild. Period.

This from the guy who says a 5 order of magnitude improvement in IEC fusion is "nothing to write home about."

If it didn't, consider what an impact such a rebuttal would have had on the ease of fund raising, and ask yourself why it isn't there.

Most likely because Bussard was dying of cancer and just didn't have time in the year and change he lived after the 12 year gag order expired, as he was busy running around showing people his experimantal results trying to get funding before he died -- and Polywell is funded, so apparently it was the right choice. The experiments will answer the questions, for good or ill.

I'm not a true believer, but I think it deserves a look. I haven't heard a great explanation for the B field power scaling. Bussard seems to claim B^4 is supported by experimental evidence, but I wonder how accurate that is, and how far that will scale.

'well, we'll have to see in the experiments' kind of comment from the advocates. Hardly convincing!

Wow, looking for experimental evidence. They almost sound like... scientists.

Posted by TallDave at October 10, 2007 09:43 AM

Oh, and a rebuttal of sorts does exist, from the Tri-Alpha guys. It's almost ten years old now.

http://www.sciencemag.org/cgi/content/full/281/5375/307a

And they got $40M in funding, so apparently no more papers are needed.

Posted by TallDave at October 10, 2007 09:48 AM

In fact they were. This was 100,000 times the comparable Hirsh-Farnsworth results at similar power levels.

And as I said, that merely shows that the other IEC reactors (which H-F fusors are instances of) are pathetic. Compared to other fusion schemes, or to the output required for a real reactor, the results were nothing to write home about.

I can run a lot faster than a man with no legs. This is not any great accomplishment.

Wow, looking for experimental evidence. They almost sound like... scientists.

Real scientists would publish in peer reviewed journals, not least because feedback from the reviewers would protect them from making extended errors. Real fusion scientists would get the theory much more nailed down before building experiments.

Posted by Paul Dietz at October 10, 2007 09:51 AM

And as I said, that merely shows that the other IEC reactors (which H-F fusors are instances of) are pathetic.

No, it shows how pathetic your arguments are. You say it's no great accomplishment to outrun a man with no legs, but giving a legless man the ability to run surely is.

Real scientists would publish in peer reviewed journals

Again, they already have funding. You are confusing the product of science with the practice.

Posted by TallDave at October 10, 2007 10:06 AM

I am Dr. Bussard's daughter. I want to thank everyone for their comments here. I have one to add myself, as to why he did not publish: your guess is correct, the gag order prohibited him from publishing for 11 years! By then he was terminally ill, and put every ounce of strength he had left into getting funding so his work could go on. He did manage to write (with great effort) the Valencia paper, which was reviewed and accepted for presentation at a conference, and I believe he planned to publish as soon as time and health allowed. I'm not a physicist so cannot comment on the other debates, but I hope this clears up at least one controversy here!

Posted by Musicgirl at October 10, 2007 07:17 PM

Musicgirl:

First of all, please accept my sympathy for your loss.

I'm not a physicist either, although I do have scientific training; but it seems to me that there is a worthwhile chance that Polywell fusion will work, and given that the cost of the research is miniscule compared to many other expenditures that the American government and other bodies are prepared to make, it seems well worth a try.

Why? Because if it works it makes civilisation energy-independent of brutal dictatorships forever, and if the extrapolation to fusion motors pans out it gives us the Solar System and maybe the stars. As another benefit, it looks as if polywell fusion plants will be relatively small and may make it more difficult for monolithic, large-scale energy companies to dominate, too.

Musicgirl, there is a reasonable chance that your father will be thought of in future ages as a combination of Prometheus and Columbus. And if it doesn't work? Well, at least he tried - most don't.

Posted by Fletcher Christian at October 11, 2007 09:47 AM

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