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Another Small Step Toward Fusion?

We’re a long way from achieving practical fusion to supply our power needs, much less fusion rockets to the stars. Just how far can be gauged by a look at current research. The principle seems straightforward: Heat hot, ionized gas to the point of ignition and you can fuse hydrogen into helium. But can you contain the plasma while you’re heating it? More to the point, can you get more power out of your device than you put in?

Most of the effort these days is going into tokamak designs that use magnetic fields to contain the plasma. But tokamaks tap plasma currents to produce at least part of the needed field. And, says John Canik (University of Wisconsin), “The problem is you need very large plasma currents and it’s not clear whether we’ll be able to drive that large of a current in a reactor-sized machine, or control it. It may blow itself apart.”

Enter the stellarator, an alternative plasma confinement method that uses no plasma currents, but one that loses energy at a high rate because the magnetic coils that generate the field are inefficient. That energy loss is known as transport, and too much of it makes fusion impossible. It would be helpful to correct that, for the stellarator brings engineering advantages in terms of designing a working fusion reactor.

The HSX-10 stellarator

Canik’s team at Wisconsin is working on a possible solution, a stellarator concept called HSX (Helically Symmetric eXperiment). It loses less energy than other stellarator designs, bringing some of the confinement advantages of a tokamak to the stellarator concept. The robustness of the magnetic field thus produced retains the energy and may make practical fusion more likely. “The slower energy comes out, the less power you have to put in, and the more economical the reactor is,” says Canik.

Image: Ungainly, isn’t it? But if it can help us toward workable fusion, we’ll live with its looks. Here we see the HSX coils and vessel on a support superstructure. Credit: University of Wisconsin.

Useful indeed, but consider this an incremental rather than breakthrough advance. The University of Wisconsin’s fusion research program has been going since the early 1960s and now includes several plasma confinement experiments. HSX’s design goes back seventeen years, a reminder that in so much of our scientific endeavor, patience is the name of the game.

Nonetheless, the latest work tweaks the confinment field interestingly, as described in this news release:

The HSX is the first stellarator to use a quasi-symmetric magnetic field. The reactor itself looks futuristic: Twisted magnetic coils wrap around the warped doughnut-shaped chamber, with instruments and sensors protruding at odd angles. But the semi-helical coils that give the HSX its unique shape also direct the strength of the magnetic field, confining the plasma in a way that helps it retain energy.

Next up is manipulating the coil design to achieve the lowest transport rate, and then figuring out ways to make the coils easier to engineer. Is a fusion generator on the (distant) horizon? The paper is Canik et al., “Experimental Demonstration of Improved Neoclassical Transport with Quasihelical Symmetry,” Physical Review Letters 98, 085002 (2007).

Comments on this entry are closed.

  • Tony March 19, 2007, 11:27

    There is another area of fusion development going on, and it’s from someone that the SciFi community will know very well

    Can I suggest that you look at the google video of Dr Bussard (yes, that Robert Bussard of ‘ramjet’ fame!) talking to some google people about work he is involved in. It’s about 90 mins long, packed with information and commentary from Bussard on what is was like to work within an environment where “there is only one way to do fusion, and that’s with a tokomak”. I found it incredibly interesting, and have watched it several times to piece things together.
    Key points;

    This is a non-thermal device – you would take electricity directly from it
    It is relatively small 1-5m (not the cathedral size tokomaks)
    There is no neutron radition – none. The system uses a Boron-11 reaction (00:05:04 into the video), which fuses with a proton to give excited C12, which decays into He4 and Be6. As Dr Bussard says (00:05:37) “This is the only nuclear energy-releasing process in the whole world that releases fusion energy as 3 Helium atoms and no neutrons”

    In typical cliff-hanger fashion, it seems their latest device was showing all the right outputs, but the project ran out of funding. Dr Bussard wants this to happen (the reason he got into fusion was as a power source for space flight), but is getting old fast. He had a slide (at 1:04:27 into the video) that said this;

    Global Economics 1:

    cheap, clean (no radiation), thermal/electric power readily available
    fixed energy prices stabilize economy
    low value cane in third world countries, becomes high value export product
    third world nations can become economically viable
    profitable industrialization possible

    And another slide at 01:04:59 (the kicker in terms of problems with Fossil Fuels)

    Global Economics II:

    Destroys world market for gasoline
    eliminates effects of oil cartels
    Oil states suffer drastic income loss, require funds to purchase food
    Desalination plants allow irrigation of arid lands
    cheap water allows effective agriculture

    And finally at 01:05:20
    Global Economics – Summary

    Low cost power stabilizes industrial nations
    Oil wars vanish
    Mid East stabilized by economics
    Third world becomes fiscally responsible

    Oh, there’s a neat slide on how to make a 100B$ business out of it at 01:05:52 ;)

    The video is at http://video.google.com/videoplay?docid=1996321846673788606

    So what does this all mean? Well, if Dr Bussard is right, and if these devices can be made relatively cheaply (he suggested it was all engineering now, the physics is done), then it doesn’t matter if the Chinese (or whomever) buy all the oil they can get their hands on, as the US would be getting its energy far cheaper than any oil source could provide – with all that entails for desalination, ecology, transport and of course, space exploitation.

  • Hiro March 19, 2007, 11:32

    I think we may have fusion propulsion in 40 years from now if we focus our research on this topic. The next step should be antimatter propulsion, but we don’t have enough antimatter because of the cost of making and holding it. Besides, CERN doesn’t have any machine that is big enough to become antimatter factory, so I doubt any antimatter propulsion would exist in the next 100 years.

    Does anyone have a plan to build a linear 1 PeV muon collider?

  • Chris Wren March 19, 2007, 12:26

    It would be bad news indeed for many futurists if fusion turns out to be impractical as a global power source. Most of the assumptions of futurism for the last 40 years or so have been dependent upon the idea of fusion as cheap, virtually free energy.

    Barring some kind of magic wand technology, fusion is still our best hope, but I think we’ll see it successfully applied to propulsion before we see fusion reactors powering the globe.

  • Administrator March 19, 2007, 12:44

    Tony, yes, we’ve looked at the Bussard concept here:

    https://centauri-dreams.org/?p=976

    Fascinating work!

  • Tony March 19, 2007, 13:03

    G’ah! – should have gone through the archives I guess. Only just put this site in NetNewsWire on Friday though ;)

  • Administrator March 19, 2007, 13:20

    Not to worry, Tony, and very glad to have you with us!

  • Paul Dietz March 19, 2007, 15:27

    Most of the assumptions of futurism for the last 40 years or so have been dependent upon the idea of fusion as cheap, virtually free energy.

    Maybe for futurists who didn’t think very hard, but there has never been a realistic prospect that fusion would or could produce ‘cheap, virtually free’ energy. The cost of nuclear power (including both fusion and fission) is dominated by capital cost, not fuel cost, and fusion reactors will be inherently more complex and therefore more expensive than fission reactors.

    BTW, stellarators strike me as a poor class of reactors for real fusion energy production. They have complex (and therefore expensive) coils, not very good beta (ratio of plasma to magnetic pressure), and have all the blanket/first wall problems of magnetic DT-burning reactors.

    If magnetic fusion is to succeed at all, advanced fuels burned in configurations with high beta will be needed, IMO. I am skeptical of Bussard’s scheme (H-11B is very difficult), but perhaps the levitated dipole concept will work out. If the physics is favorable, it may be able to burn just deuterium (spiked with 3He bred by the nuclear reactions in the reactor). No tritium breeding blanket would be needed.

  • Dennis March 19, 2007, 18:11

    Trying to get workable fusion reactor is like climbing to the summit of Everest back in 1940-50s. The best solution is to exploit all possible paths that may leed to the finish, be it tokamak, stellator, levitated dipole, inertial electrostatit (Bussard) and the rest. The first method to achieve controlled and useful fusion (I believe in ITER ultimate success to do this, btw) need not to be most efficient, and maybe soon surpassed by other types that took more time to develop, but proved to be hundredfold more powerful. Dear nuclear/plasma scientists – just keep on researching! :)

  • pfdietz March 20, 2007, 8:43

    The best solution is to exploit all possible paths

    This solution is not feasible, since the money is not available for it. Fusion budgets are surprisingly small — the annual US magnetic fusion budget is roughly half the cost of one space shuttle launch (at average shuttle launch rates, averaged over the life of the program, divided by the current cost/year of operating the vehicle).

    But even with larger budgets, this would just push back the boundary at which the choices would have to be made, it wouldn’t eliminate the choices.

    The first method to achieve controlled and useful fusion (I believe in ITER ultimate success to do this, btw) need not to be most efficient,

    The problem is not ‘efficiency’, the problem is cost. Tokamaks appear to me to have little chance of competing economically with more mundane sources of electrical power (fission, wind, etc.), particularly given the improvements in those competitors in the decades before tokamaks can come online.

  • eric wood March 20, 2007, 8:56

    So does anyone know, where does Dr Bussard stand on his funding request with GOOGLE?

  • Administrator March 20, 2007, 13:17

    Eric, as far as I know Google is still considering Dr. Bussard’s work but nothing definite has been announced. As soon as I hear of anything, I’ll pass it along, and if any of our readers have further info, please chime in. To be honest, I will be surprised if Google puts money into this but we’ll see.

  • ljk April 4, 2007, 8:47

    Caltech Today Alerts for April 4, 2007

    News and Information from Caltech Today – http://today.caltech.edu

    TWISTED FLUX TUBES EXPEL “WRONG-WAY” IONS (TOP STORIES)

    Researchers at Caltech have identified a new way that plasma
    undergoes certain types of magnetic confinement degradation observed
    in the laboratory. Greater understanding of magnetic confinement
    could be crucial for future electric power plants that harness
    nuclear fusion, the powerful process fueling the sun.

    Details: http://mr.caltech.edu/media/Press_Releases/PR12964.html

  • M. Simon April 19, 2007, 8:38
  • Administrator April 19, 2007, 9:00

    Nice catch! This is good news, though it’s well below the funding levels he was hoping for. Still, the extra from the Navy should keep Bussard’s work going while he looks for a larger benefactor.

  • george scaglione April 19, 2007, 14:10

    good to see all of the above and god speed fusion!! a logical first step before antimatter and other things even more sophisticated ! but did somebody say 40 years of wait?! i prefer a little sooner than that…but thats just me lol !! funny in another venue i just made a wild guess about space planes and other ssto vehicles that is that kids born long about 2015 will not understand why we did not always have something so “simple”.well thank you one and all respectfully your friend george

  • ljk April 26, 2007, 9:33

    Fusion energy breakthrough at Sandia Labs

    KurzweilAI.net Apr. 25, 2007

    *************************

    An electrical circuit that should
    carry enough power to produce the
    long-sought goal of controlled
    high-yield nuclear fusion and do it
    every 10 seconds has undergone
    extensive preliminary experiments
    and computer simulations at Sandia
    National Laboratories. Circuits on
    an LTD device able to produce large
    electrical impulses rapidly and…

    http://www.kurzweilai.net/email/newsRedirect.html?newsID=6722&m=25748

  • ljk May 7, 2007, 16:39

    Navy Heats Up Cold Fusion Hopes

    Daily Tech May 5, 2007

    *************************

    Scientists at Navy’s Space and
    Naval Warfare Systems Center
    (Spawar) claim they have achieved a
    low energy nuclear reaction (LERN)
    in an experiment that can be
    replicated and tested. They coated a
    thin wire with palladium and
    deuterium, then subjected it to
    magnetic and electric fields. The
    researchers have offered plastic
    films called CR-39…

    http://www.kurzweilai.net/email/newsRedirect.html?newsID=6768&m=25748

  • Timothy J Mayes June 25, 2007, 20:42

    A very high power version of the vasimir plasma engine can potentially achieve nuclear fusion if you use duterium /tritium plasma gases as the propellant , and you heat them to 100,000,000 to 400,.000,.000 celcius inside it

  • ljk July 24, 2007, 23:42

    Governor Schwarzenegger to research Revolutionary Radiation Free Fusion Reactor

    In a move sure to impress environmentalists and further cement his Earth friendly image, Governor Schwarzenegger is set to launch a multimillion dollar research effort into a revolutionary new source of clean non-polluting power.

    The reactor works by using Quasi-spherical magnetic fields that trap injected energetic electrons to form a spherical negative potential well. Fusion ions trapped in this spherical well focused through central region oscillate across the “core” until they are reacted.

    The project is focused on the Inertial Electrostatic Fusion reactor invented by the award winning American physicist Dr. Robert W. Bussard. The Radiation Free Fusion Reactor has the potential to change the whole landscape of energy generation, which is usually a choice between bad and worse options that include Nuclear, Coal and Natural Gas systems.

    Full article here:

    http://www.nextenergynews.com/news1/nextnews7.24b.html

  • ljk October 9, 2007, 10:27
  • ljk October 9, 2007, 14:01
  • James M. Essig January 25, 2008, 5:29

    Hi Folks;

    It occured to me that the most exothermic fusion reactions convert about 0.7 percent of their mass to fuel. If it were possible to design a fusion powered ion rocket in which 99 percent or greater of the net energy release of this fusion reaction could be converted into ion rocket or electron rocket thrust, perhaps Isp considerably greater than the often stated maximum of 2,500,000 for fusion rockets could be obtained.

    To see why, lets use the relativistic mass increase equation Mrel = Mrest/{[1 – [(V exp 2)/(C exp 2)]] exp 1/2}. Let us use the value of 35,500,000 meters/sec for V. This yields a relativistic mass increase of a factor of 1.0071 which works out to the value of 0.7 percent of the mass of the fusion reactants being converted to ship based kinetic energy. This could in theory lead to an Isp of about 3,5500,000.

    For an Isp of 2,500,000 which is an often quoted limit for fusion rockets, a fuel to dry weight ratio of 1/55 will get you to a speed of 100,000,000 m/s or 1/3 C. If effecient magnetic breaking or reverse magsail breaking was used to slow the craft down, 2,500,000 Isp fuel could get mankind to Barnard’s star in about 18 years. If reverse thrust were used, then an Isp of 2,500,000 and a fuel to final dry wieght of 55 exp 2 = 3025 would get us safely there.

    Now with an effective Isp of 3,550,000 the mass savings are very dramaticallly improved. In fact, using a fuel mass to final dry wieght of about 10,000 to one should enable one to approach gamma factors high enough wherein relativistic time dilation effects become a very important consideration for manned missions to the few Sun like stars which are within roughly a 10 light year radius of Earth as well as destinations further abroad.

    Reactants of the hydrogen fusion reactions such as helium could be processed in nuclear fusion reactions wherein the energy produced would be used to power an ion or electron rocket, wherein the net effective Isp for the reaction mass increases significantly over that of the first stage of fusion reaction. If in turn the products of helium fusion are then fused wherein the energy released is then used to power such electrical propulsion systems, the effective Isp goes up another significant jump over that of just the fusion of the initial fusion fuel. One can persue fusion reactions all the way up to the most stable form of Iron at which point no further net energy release occurs to yield maximize specific impulse with respect to the initial starting hydrogen fuel. Fusion reaction sequences should be chosen inorder to maximize the amount of mass converted into energy in forms easily recoverable.

    The use of energy collection mechanisms to capture the fusion energy include electrodynamic charged particle extraction mechanisms, heat absorbing vessels for capturing nuetrons and gamma rays and the like wherein the heat would drive turboelectric generators of the utmost effeciency. Secondary, tertiary, etc., turboelectric power generation systems that utilize progressively cooler phase change working fluids could extract as much energy as possible out of the heat generated by the fusion reactions. Ultimately, perhaps using a combination of nested turboelectric systems, low temperature thermoelectric materials, and superconducting materials near the outer hull of the ship to convert thermal low temperature microwave radiation to electrical power, virtually none of the generated energy would be lost from the ship other than in the form of charged particles used as a reaction mass.

    The fuel could be processed in batch mode wherein a small batch would be processed up to iron at which point the next small batch would used the iron produced from the first small batch as a reaction mass and so on until all of the fuel was expended. The iron would be ejected as ions and electrons by electrical rockets wherein the electrodynamic energy released from the ion accellerators not in the form of reaction mass would be recycled and resused to help power the accelleration of subsequently ejected ions.

    Perhaps the fusion reactions could occur using very small initiating quantities of antimatter which could be stored on board the ship.

    Such efficient multistage fusion sequence powered space craft would be very challenging to design especially interms of the waste energy recovery systems but such R&D efforts would no doubt improve the knowlegde of gaining lost energy back into systems such a biospheres within huge many generation space arks designed to travel for millions if not billions of years ship time in intergalactic space.

    That’s all for now.

    Thanks;

    Your Friend Jim

  • george scaglione January 25, 2008, 9:39

    jim and everybody – it is so good to see that this subject has received and is receiving so much serious thought. one thing and another,if i had to make a wild guess i’d say we will probably have a fussion engine flying in about 20 years! what does anybody think!? thank you george

  • James M. Essig January 25, 2008, 18:44

    Hi George;

    Thanks for the comments. I would say 20 years is as good as any simmilarly near term guess. I think as we plan to do manned expeditions out into the solar system, we will soon see the great limitations of ordinary chemical rocket fuels. If Hillary gets elected, that is good news for the space program. I think we can expect to see a lot more emphasis on nuclear propulsion in the comming two decades.

    The beautiful thing about fusion fuel is that it is everywhere visible and potentially extractable even for new improved versions of interstellar ramjets that might work, especially with unforeseen conceptual improvements, to essentially reach unlimited gamma factors. It is cool to realize that even sub-C inertial travel through space time can in theory eventually allow arbitrarilly high multiples greater than unity of recessional velocity from Earth, given the expansion of spacetime itself. One simply needs to travel inertially out to a distance of about 13.7 billion lightyears from Earth, and lo-and-behold, their relative velocity with respect to Earth and the local Galaxy group will surpass C from space time expansion alone. This can be accomplished even for mildly relativistic space craft traveling at 0.1 C given enough time to reach a region during which the space time expansion based recessionary velocity in itself becomes greater than C. For our universes rate of expansion, assumming it remains constant, this velocity of 0.1 C will reach such a location of about 13.7 billion lightyears distance from Earth in 137 billion years which should be doable via a very large, very low energy emmission, long term humanity inhabited fusion powered space hab.

    Oddly enough, if the size of our universe in space is infinite, that means there is a infinite amount of energy available to be harnessed for space craft propulsion in the form of hydrogen and helium in the direct path of the transiting space craft.

    Perhaps as the fusion powered spacecraft’s gamma factors continued to increase, the craft might experience some sort of “doubly special relativity” based faster than the special relativistic value of C through the vacuum of space. Note that in double special relativity, the exact special relativistic value of C is for the long wavelength limiting value of electromagnetic radiation. The rate of increase above C with respect to radiation frequency increases is very very small and yields currently undetectable results even for gamma rays produced in ordinary nuclear reactions. However, as radiation photon energy levels approaches that Planck Energy of about 1.956 × 10 EXP 9 Joules = 1.22 × 10 EXP 19 GeV = 0.5433 MWh, the velocity of the respective photons according to some versions of double special relativity mounts sharply. Note that Eplanck is equal to Ep = {[(h bar)(C EXP 5)/G] EXP 1/2} where h bar is the reduced Plancks constant, C is the special relativistic velocity of light, and G is the universal gravitational constant.

    In fact according to some versions of doubly special relativity, early on in the universes first instants, the photon energy was so high that the speed of the thermalized radiation through space was practically infinite thus possible offering an alternative explanation for the observed homogeniety of the observable universe and presumably beyond.

    That’s all for now.

    Thanks;

    Your Friend Jim

  • george scaglione January 26, 2008, 14:12

    jim yes sir no doubt that the quantity of fuel we might be able to harness for space flight is or certainly borders on the infinite!and yes again for those of us that have an interest in space hillary certainly seems to be the best candidate.i agree with you.lol does eveyone else!? we can hope. have a good day george ps about that fusion engine guess,20 years if not sooner, is what i think! you betcha! ;) g

  • James M. Essig May 9, 2008, 7:19

    Hi George;

    Speaking of fusion rockets, it occurred to me that interstellar ramjets might use an electron and/or proton or ion beam wiggler like a free electron laser mechanism to extract energy out of an incomming focused beam of charged particles derived from the interstellar medium by interstellar ramjets traveling at moderately to highly relativistic velocities. Once the relative kinetic energy of the charged particles was extracted, the left over nuclie could be fused to provide the net energy required to accellerate the space craft even further.

    I am not an expect on interstellar ramjet concepts and am unfamiliar with the latest and greatest ISR concepts, but I think an electrodynamic mechanism for converting the incomming plasma’s kinetic energy to electromagnetic energy is a good way to efficiently reduce the relative velocity of the plasma with respect to the ship wherein the plasma could then be used in nuclear fusion reactions and as a reaction mass to power the ISR.

    Another electrodynamic method for extracting incoming plasma energy is to allow it to enter some sort of cyclotron type mechanism to produce synchrotron radiation wherein the radiation would be collected and recycled to cancel out the effect of the momentum of the incident interstellar medium with respect to the ship.

    A supply of antimatter might be brought along with the ship to catalyze the nuclear fusion of the nuclei as the nuclei are slowed and collected after entering the ships intake.

    Interstellar ramjets, although not as popular of a concept as they use to be, intrigue me because they can possibly effeciently harvest fusion fuel from the interstellar medium, perhaps even from the intergalactic medium and thus do not require the carrying of an initially very large supply of fuel.

    Thanks;

    Your Friend Jim

  • James M. Essig May 27, 2008, 17:50

    Hi George;

    Regarding fusion powered spacecraft and electrical power generation, such would indeed be fantastic. Projects like the planned International Test Facility and the National Ignition Test Facility with in the U.S., I hope, will prove invaluable for fusion energy development.

    In the mean time, we have good old fashion fission reactors which could prove valuable for manned excursions into the Kuiper Belt, Oort Cloud and even in generational or multi-generational space arks to our stellar neighbors.

    I have read of concepts wherein spent fission reactor fuel remains could be burnt in fission processes to increase the net energy gain from the fission decay sequences of nuclear fission reactor fuels.

    Perhaps there exist stable super-heavy elements within the so-called Island of Stability wherein the rest mass specific energy release of these yet to be produced nuclei would rival or surpass that of nuclear fusion fuel. The caveat here is producing such exothermic fuels in large enough quantities to be useful for manned interstellar space craft.

    Another possible alternative is to utilize nuclear fission breeder reactors to produce adequate quantities of fission fuel from safely storable high atomic number elemental-isotopic material stocks thus reducing the risk of the formation of a critical mass when storing large quantities of material from which energy can be derived. To achieve 0.1 C or 0.2 C with fission reactor powered space craft, probably several times the dry weight of the ship in terms of fuel stock or potential fission fuel stock would be required. But, I get a feeling that such is doable since we understand nuclear fission, related radiation shielding, and energy extraction processes very well.

    We could in theory send huge nuclear powered space-ship worlds out all over the observable universe. In a trillion years Earth time or ship time at 0.1 C, we could travel a distance and thus populate out to a distance of 100 billion light-years not taking into account space-time expansion within our universe.

    Thanks;

    Your Friend Jim

  • Adam May 28, 2008, 17:33

    Hi Jim

    Fission fragment drives get an exhaust velocity of ~ 0.04 c at top performance, but usually it’s lower due to the difficulty of getting a strong jet from pure fission. A nuclear saltwater rocket can get ~ 4,700 km/s exhaust velocity, according to Bob Zubrin’s work. Coupled with magnetic sails you might get to ~ 0.03-0.04 c in useful time. Trying for big mass-ratios just isn’t feasible with standard rocket scenarios because of the storage issues of fissionables.

    A while back Dana Andrews concocted a scheme to send pellets of fuel to a starship, use it in a fission fragment drive, and slowly crawl to 0.1 c. Since then Andrews has turned to Jordin Kare’s micro-sail scenario and Andrews’ own design for MagOrion. Conceivably a fission-fuel pellet might be launched via a micro-sail launcher, but the additional energy gain seems small for all the effort involved.

    Question is: where will all those fissionables come from? And how will they be produced cheaply enough?

  • James M. Essig May 28, 2008, 23:06

    Hi Adam;

    Thanks for the information on fission fragment exhaust velocities and nuclear saltwater rockets augmented with magnetic sails. 0.03 – 0.04 C would put us at roughly 10,000 – 13,000 km/sec. Perhaps the fission fuel precursor stock could be stored as some long half-life very high critical mass fuel upon which breeder reactors would operate to change the fuel to highly fissionable fuel.

    The point about big mass-ratios is well taken. Even U-238 or depleted Uranium will, I believe, form a critical mass in a large enough aggregated mass. U-238 was used in certain high yield fission-fusion-fission types of atomic bombs wherein the neutron flux generated by the fusion stage would interact with the device’s outside layers of U-238 to induce fission.

    Perhaps a safe breeder reactor feed stock can be used wherein many times the dry weight of the space craft can be carried along the mission. The feed stock might be safely towed behind the spacecraft like bobbers on a fishing line so as to allow adequate spacing between the stock sub modules to prevent critical mass from developing. The tow lines might be made of carbon nano-tubes, graphite fiber arimid, or the like high strength materials. Smaller acceleration values would permit thinner tow lines or greater tow masses.

    Either way, if 0.3 C would be the limit, we could still travel out to 30 billion light-years from the Milky Way in 1 trillion years ship time, even much farther yet if one assumes overall constant space-time expansion. Perhaps the asteroids could be an excellent source of such breeder reactor feed stock isotopes. The caveat, how to maintain a ship based civilization over 1 trillion years in a confined environment.

    Thanks;

    Your Friend Jim

  • ljk May 29, 2008, 14:48

    Focus fusion has agreement with CMEF of Sweden

    Focus Fusion has received funding of $600,000 with phased additional payments up to $10 million.

    Lawrenceville Plasma Physics, Inc. (LPP) has announced the signing of its first licensing agreement for the manufacture, distribution and marketing of focus fusion reactors. The reactors, which could produce energy safely and for far less than current costs, are under development by LPP, which expects them to be ready by 2012. The agreement gives Center for Miljo-och Energiforskning (CMEF), a Swedish firm, a license to manufacture, market and distribute focus fusion reactors in the European Union and Norway in return for phased payments to LPP of $10 million, with an option to extend the license to Russia for an additional amount. Payments past the initial year’s $600,000 will be conditional on proof of the scientific feasibility of focus fusion. CMEF is a start-up clean energy firm, with interests in new technologies, including focus fusion.

    Focus fusion reactors will use a small device called the dense plasma focus to produce energy by fusing hydrogen and boron. The energy is released in the form of charged particles, which can be converted directly into electricity, without using the normal, expensive process of producing steam and running it through turbines. LPP has been developing the technology since the 1980’s, partly with funding from NASA’s Jet Propulsion Laboratory. It is currently engaged in a three-year experiment in collaboration with the Chilean Nuclear Energy Commission to demonstrate the scientific feasibility of the process. If these experiments are successful, another three years will be needed to develop a prototype reactor ready for manufacture.

    From the focus fusion FAQ:

    It is like a particle accelerator run in reverse. Such an electrical transformation can be highly efficient, probably around 80-90%. What is most important is that it is exceedingly cheap and compact. The whole apparatus of steam turbine and electrical generator are eliminated. A 20MW focus fusion reactor may cost around $500,000 and produce electricity for 1/20th of a cent per kWh. This is a hundred times less than current electric costs. Fuel costs will be negligible because a 20MW plant will require only twenty pounds of fuel a year.

    Full article and diagrams here:

    http://nextbigfuture.com/2008/05/focus-fusion-has-agreement-with-cmef-of.html

  • ljk May 30, 2008, 12:38

    Cold-fusion demonstration “a success”

    On 23 March 1989 Martin Fleischmann and Stanley Pons
    announced that they had observed controlled nuclear fusion…

    http://physicsworld.com/blog/2008/05/coldfusion_demonstration_a_suc.html