The grandmother of the Polywell, called a Hirsch-Farnsworth Fusor, was invented by Philo Farnsworth, one of the inventors of television. It was essentially a spherical grid (a metal screen) negatively charged to as much as 100,000 volts, and placed at the center of a vacuum chamber. Deuterium (D2) gas was puffed into the chamber. The gas was immediately converted to positive deuterium ions (D+) by a positive screen (not shown) just inside of the Vacuum Tank Shell. The negative 100,000 volt screen attracted and accelerated the positive ions to such a high velocity that a few of them whizzed right through the metal mesh, and collided with other similarly accelerated deuterium nuclei at the center of the spherical grid. They were traveling so fast by then, that when they collided, they fused to make helium. Unfortunately, the ions often missed each other and passed on through the other side of the grid. Two percent of them were lost to the negative grid every time they tried to pass through it; and since they passed through it a LOT of times, two percent was just too much: the machine used a lot more energy than it made. However, this may be the easiest way for humans to do fusion at this time. Go here to see how you might build your own fusor.
The mother of the polywell was the Elmore-Tuck-Wilson (ETW). It used a spherical POSITIVE (+) grid, instead of a negative one; and instead of accelerating positive ions into the center, it accelerated negatively charged electrons (e-). The idea was to create an extremely dense negative concentration of electrons (called an electron potential well) at the center of the grid, and let that concentration of electrons attract the positive deuterium ions (D+) which would again be created by the ionization of Deuterium gas sprayed into the system just inside of the positive grid. Again, the idea was to accelerate the deuterium ions to such a high velocity that they would fuse at the center. (The electrons and ions at the center are traveling so fast that they do not recombine to any significant degree.) Unfortunately, this time the problem was a two percent loss of electrons to the grid, on each pass; so again, even though some fusion was happening, the losses were too great.
Robert W. Bussard
The ETW Reactor and the tokamak were the key ideas that led to Robert Bussard’s invention of the polywell. Dr. Bussard had designed a small tokamak, called the Riggatron in the late 1970s. These efforts led him to think seriously about how to get around the problems plaguing tokamaks. He had the thought that it was a shame ions are so much more massive than electrons, because a tokamak would be able to confine electrons at high density far more easily than it was able to confine its tritium and deuterium ion fuel. Then he thought about the ETW reactor and serendipity struck. He began to wonder if the ETW reactor might actually work if its positive grid could be magnetically shielded from the electrons, to keep them from getting lost when they struck the grid. And so was born the idea of the Wiffle Ball - a "quasi-spherical" magnetic field inside of the positive ETW grid, into which one could inject electrons. He thought that if he could place a circular magnet on each face of a cube, with each magnet pointing the same magnetic pole inward, it might form a working magnetic bottle for the electrons. By 1987 he had become so confident in the concept, that he had formed a new company, Energy/Matter Conversion Corporation – EMC2 – to research it.
But we are getting way ahead of the story. To better understand how Robert Bussard got to the Polywell, we need to go back to the early 1950s, when he invented the NERVA program.
In his final October 2007 interview with Tim Ventura, he said, “I wrote a paper on nuclear rocket propulsion in 1953 when I was at Oak Ridge National Laboratory…that seemed to attract the attention of the Air Force…the result was the start of the national nuclear rocketry program in the spring of 1955 at Livermore and Los Alamos…we ended up with a 250,000 ton thrust engine that could be cycled 40 times on and off…we ran hydrogen through graphite cores at very high temperatures …that gave specific impulses 2.5 to 3 times higher than anything you could obtain from chemical propulsion…the program ended up being controlled by NASA who intended to use it for a 1978 manned Mars mission … (but) the program fell flat due to …wars between the chemical and nuclear rocket communities, the budget office, and between Livermore and Los Alamos. Along came the Vietnam war and…killed everything…fifty years ago, we had nuclear rockets that could take people to Mars!”Robert was born in Washington, D.C., in 1928. At age 7, his family moved to California where his father had a company and practiced civil engineering. He flunked out of Cal Tech, and entered UCLA after a road trip to Chicago. He graduated with a degree in engineering in 1950 and received a master's degree two years later. After working at Hughes Aircraft and Whirlajet, he joined the Oak Ridge National Laboratory. He was recognized in 1960 for his design of the Bussard ramscoop interstellar space drive (right), made famous by Carl Sagan in his Cosmos series and by such science fiction authors as Larry Niven and Poul Anderson.
Ironically, in the early 1970s, when he was an assistant director of the AEC, he founded the U.S. tokamak fusion program. Much later, in a June 6, 1995 letter to congress, Bussard tried to put an end to the tokamak boondoggle he had created. He explained, ”…DoE (the US Deparment of Energy) is almost certainly not ever going to give the nation any safe, technically viable, or economically useful fusion power plants or systems. …DoE commitment to…(the giant magnetic tokamak) ensures only the need for very large budgets; and that is what the program has been about for the past 15 years – a defense-of-budget program, not a fusion achievement program. As one of the three people who created this program in the early 1970s (when I was assistant director of the AEC’s Controlled Thermonuclear Reaction Division), I know this to be true; we raised the budget in order to take twenty percent off the top of the larger funding, to try all of the things that the mainline labs would not try. Each of us left soon thereafter, and the second generation management thought the big program was real. It was not.”
In 1987, he started his own company, EMC2.
Tom Ligon describes the first time he met Robert Bussard, “Imagine you're a science fiction author, discouraged with your old job and about to quit and start a consulting business. You get wind of the fact that there's someone in the area working with high vacuum equipment, whose last name is Bussard. So you think, Bussard, vacuum, space, fusion, interstellar ramjets? The inventor of the gizmo behind science fiction classics like Tau Zero, the Ringworld stories, and many others? Could it be that Bussard? So I found the address, dropped by with my newsletter, résumé, and an introductory letter, and knocked on the door of the little office two miles from my home. Nobody was there, but the sign by the door declared that it was the Energy/Matter Conversion Corporation. I slipped my propaganda under the door, smiling as I got the connection to Einstein's famous formula.’
“Some moments you just never forget. A few weeks later I was sitting at my computer when my business phone rang. I answered eagerly (that thing didn't ring much), and the voice on the other end called himself R.W. Bussard, and wondered if Tom Ligon was available. ‘I certainly am,’ I said, ‘but I just have to know if this is the Robert W. Bussard, as in interstellar ramjets?’’
" ‘I guess I'll never live that down,’ he admitted, and then he invited me in for an interview.”
Ligon got the job. He describes Bussard in his Analog essay, The World’s Simplest Fusion Reactor Revisited, “His career stems from a very early and intense desire to make spaceflight practical…he literally "wrote the book" on nuclear rocket propulsion. His first degree was as an engineer, and only after developing the first working fission rocket engine did he head off to Princeton to earn his Ph.D. in physics. And, while he is a first-rate physicist, he still has the heart of an engineer and inventor. It was always great fun to watch him at a blackboard, NRL Plasma Formulary in one hand, chalk in the other, working problems faster than I could follow them with a calculator.”
Ligon continues, describing the first Polywell team, “Dr. Nicholas A. Krall is one of the best theoretical plasma physicists ever, and has collaborated on this project from the start. Lorin Jameson is a computer whiz and physicist that put the math of Bussard and Krall into functioning computer programs like EIXL, to analyze the data from the experimental runs and predict performance of larger systems. Later on, Mike Wray, Mike Skillicorn, Ray Hulsman, and Noli Casama were the ones who made the machine that finally worked. And none of this would have happened without EMC2 president, Dolly Gray, the only person on Earth who can make R.W. Bussard do what he needs to do when he doesn't want to.”
The first EMC2 laboratory research efforts began with the WB-1 in 1994. The positive magnetic grid (magrid) was made out of six 5 cm radius, uncooled, ceramic speaker magnets -much like refrigerator magnets- in metal cases welded together as shown on the right. The magnetic field was compromised by the “line cusps” where the magnets were fastened together at the edges. Electrons tend to follow magnetic lines of force; and since the lines of force terminated at the “line cusps”, the electrons were lost there. Nevertheless, some electrons were indeed trapped. The WB-2 had wound wire coils instead of ceramic magnets. The WB-3 (1998-2001) was much the same as the WB-2 except that the coil radius with was 10 cm. The WB-4 produced 10^6 fusions per second. Its magnets were water-cooled, their radius was 15 cm, the grid voltage was 12,000 volts, and the depth of the potential well produced by the trapped electrons was about 10,000 volts.
The insights gained from the WB-5 led to the improvements, which were applied to the WB-6: rounding the coil cross-sections, and separating them so they did not touch at the edges. The WB-6 (right) was hastily built and tested in October and November of 2005. It produced about 1 x 10^9 fusions per second, which was over 100,000 times better than all previous work at comparable grid voltages. Because of power supply limitations, and problems with overheating of the coils, all testing was short-pulsed. The coils were wound from plain varnish-insulated magnet wire, with no cooling mechanism. The wire got very hot, very fast. Also, the configuration of coils on any Polywell produces mutual repulsion, so the coils press against their containers trying to get away from each other. The individual windings also tend to mutually repel. Both of the previous magnet-wire machines had reached end-of-life due to coil blowouts, and this one was hammered even harder.
But at the same time, at the moment of their greatest success, their budget was cut. Bussard explains, “The reason our funding died –is not because the Navy did anything– but rather because of the Iraq war. The Iraq war budgets have been consuming everything in sight in Washington and when it came time for the budget process for fiscal 2006, the total Navy R&D budget was cut by twenty-six percent across the board. One of the cuts was the Navy Energy Program. We were a victim of that. We were a little pimple, down in the noise of the thing, but we died along with it. We had some friends in (the Office of Naval Research) that kept us alive for 9 months and that was it.’“We had a plan where we had to close down by the first of November 2005 and start getting rid of all the equipment since there wasn’t any way to carry it past the end of the calendar year. … but we were approaching November first and we hadn’t tested the heavy fusion conditions (with the WB-6) yet. I said, ‘But we have to finish this,’ so we kept on working past the shut-down date.”
Nearly a year after shutting down the lab, Bussard presented his work — for the first time in more than a decade — to the International Astronautical Congress. He later discussed his results with Google, the online search-engine company, in a talk titled, "Should Google Go Nuclear?" that is widely available on the Internet. In a letter to an Internet forum on his 2005 results, Bussard wrote that he believed, "…the survival of our high-tech civilizations depends on getting off of fossil fuels ASAP, and –if we do not– we will descend into a growing series of 'oil wars' and energy confrontations that can lead only to a huge cataclysm. Which can be circumvented if only we build the clean fusion machines in our time…the political reality is that oil companies have no interest in supporting fusion research…There is only one thing the oil companies want, and that is to sell oil, and more oil…The only way to stop oil, from their view, is when it does run out. And then they'll go for deeper drilling, new fields, … LNG, etc. etc., and keep raising the price, until finally foolish solar and windmills become competitive."
More recently, Tom Ligon reported, “Dr. Bussard did, with the help of Alan Roberts -EMC2's longtime Navy contract monitor- get 1.8 million in government funds in August 2007, and he managed to put together another crack team. He passed away in October (he had been dreadfully ill since shortly after the old lab closed). That was a really sad time, but the new team (headed by Richard Nebel on leave from Los Alamos National Laboratory) is working especially hard to see the dream thru. They achieved "first plasma" with the WB-7 in early January 2008, and I am hoping for great news soon. Their goal is to reproduce the WB-6 (results), improve on it, and have it hold together for peer review. Speaking about Robert Bussard, Richard Nebel said, "I've met and worked with a lot of really smart people. Not many were real innovators, and that's what he was. He would try to do things other people said you couldn't."
Bussard's wife, Dolly Gray, who co-founded EMC2 with him in 1985 and served as its president and CEO, has helped assemble the small team of scientists in Santa Fe. Besides Nebel, 54, the group includes Jaeyoung Park, a 37-year-old physicist who is also on leave from LANL; Mike Wray, the physicist who ran the key 2005 tests, and Wray's brother, Kevin, who is the computer guru for the operation.
"If this works, it's going to be a big deal. It could take the entire energy market," Nebel said. "And drag the oil companies into the 21st century," Gray added.
Richard Nebel and the new Polywell team went on to build the WB-7 Polywell to validate Robert Bussard's discoveries. The work was peer-reviewed in the fall of 2008; and on the basis of that work, the Navy called for bids on a new contract for a larger WB-8 Polywell to verify the r^7 scaling principle and the p-B11 reaction.
EMC2 got the new contract as well. It was for nearly $8 million dollars. As of June 2011, Dr Jayoung Park and his team are more than half-way through the new contract, at their new WB-8 research operation to San Diego. If the r^7 scaling principle and the p-B11 reaction are verified, the next contract should be for about $350 million dollars, and it should call for construction of a full-scale 100 megawatt polywell.
In November 2010, Richard Nebel stopped working for EMC2, and Jayyoung Park became manager of the project. Nebel was only 57 years old in 2011, and is still doing research in Physics. He works for Tibbar Technologies, presented a paper at Wisconsin State University at Madison on October 11, and will present another physics paper at the APS Plasma conference in Salt Lake City November 14-18. It seems resonable to ask why Dr Nebel is no longer with EMC2? He has made no secret of his belief that a full-scale 100 megawatt polywell is the most reasonable next step. So my best guess would be that when it became apparent that our present administration and the US Navy were not headed in that direction, Dr. Neble left in frustration. (To be clear, let me re-emphasize that this is ONLY A GUESS - unsupported by any quotes or facts!)
In view of the much larger cost of the next step, and in view of the present economic situation, it is very important for all of us to stay in touch with with our senators and representative - to assure that this vital work continues to move forward.