Slashdot Mirror
Build a Nuclear Fusion Reactor at Home
FridayBob writes "For those of you tired of waiting around for someone else to achieve the holy grail of physics, now's your chance to beat 'em all to it. All you need is some basic engineering skills, this site and the inspiration necessary to make your very own 'fusor' produce more energy than it consumes. Hopefully, you'll have more luck than its inventor, Philo T. Farnsworth, who first built it in the 1950's after inventing the television some 30 years earlier. If you run into problems you'll be able to count on a enthusiastic support group, as the contraption seems to have developed a cult following over the past few years. Okay, so I'm skeptical that this approach will ever really work, but at the very least it sounds like a really cool science project!"
There was a kid who tried building a reactor once for his Boy Scout merit badge, and he got arrested for it. Do you want to risk that?
Pass.
Is this truly the only Earth I can live on?
This story is an example of someone who actually tried to do something simmilar.
Its a fantasticly strange and scary story.
Mouse powered Chips, Open source Processors and Lego
Finally I can get a Mr. Fusion to power my Flux Capacitor.
http://www.kubuntu.org/
" Lisa in this house we obey the law of thermodynamics!"
Whether or not this ever works, TV will go down as Farnsworth's most detrimental contribution to humanity.
I'm a signature virus. Please copy me to your signature so I can replicate.
Wha, I was under the impression that John Logie-Baird invented television... what gives?
Ahh, I get it now, Philo T. Farnsworth is an American, right?
But the most compelling promise of fusion is in the fuel itself: fusion is produced from an isotope of hydrogen called deuterium, which exists in the Earth's oceans in sufficient abundance to supply the planet's energy needs for hundreds of millions of years - until long after the Sun itself has flamed out.
The sun is supposed to burn out in 5 billion years, I believe.
Before everyone gets started on their arguments about who invented television (thanks submitter!), please read through the comments on this article. Unless you have newly unearthed evidence, please leave it alone as it has been discussed to death. Ok? Thanks.
I guess that's what Pons & Fleischmann should have been looking into...
It seems making a nuclear reactor these days makes you an automatic member of the axis of evil. So now I can claim slashdot promotes terrorism!!!
because then he would have wound up with a
NUCLEAR POWERED TELEVISION SET!!
now that's a plasma screen worth looking at...
Not really surprising from the guy who invented the Smelloscope..
Escher was the first MC and Giger invented the HR department.
I'd trust an inventor named Farnsworth just as much as I'd trust a physician named Zoidberg.
I once shot a man in Reno 'cause they cancelled Firefly.
I PITY da foo who try to make fu....sor!
Hehe... wonder if Hubert J Farnsworth is a relative of his :)
;)
The article would have been better if they started with 'Good news everyone...'
"Hey! Unless this is a nude love-in, get the hell off my property!!"
What a load of crap. Good luck. These reactors require more energy to run than they produce. And D2 (deuterium gas) isn't cheap either. As for the oceans having enough deuterium to let us outlast the sun... cods whallop. There's obviously a mis count there, or the numbers are fudged. Maybe if you produced such a small amout of energy that one could make it last longer that's possible, but the Sun contains more matter than the rest of the solar system combined. The Earth's oceans arent' even a drop in the bucket (pardon the experssion).
The energy gain, or lack there-of, is why there are no commercial fusion reactors, energy output doesn't off-set cost and energy input. -- It's not like fusion hasn't been achieved! It has. You may even want to check out the muon catalyzed fusion reactions that were being done right up until a year or so ago at TRIUMF in BC Canada, same problems there too... and that was the most promising in a long time.
Now we don't have to develop a static powered car, but can rather make a Mr Fusion to power the Flux Capacitor so we can go to the future where all of life's problems are already solved!
Link: Naturally, knowledge regarding the safety aspects of such an effort is essential! Among the more common concerns are the work
with the explosive hydrogen gas, deuterium. High voltage hazards abound as over 20,000 volts is needed to
accelerate the deuterons. Radiation in the form of X-rays and neutrons must be dealt with as well.
Where is the kids-don't-try-this-at-home-disclaimer?
If at first you don't succeed, then sky diving definitely isn't for you.
"Temporarily Unavailable The Tripod page you are trying to reach has exceeded its hourly bandwidth limit. The site will be available again in 2 hours! Thank you! "
I want one NOW!
Matter-antimatter reactions produce gamma rays and other high-energy radiation. In order to harness this energy, you need to convert it into electricity, which requires actually absorbing the radiation. But since gamma rays laugh at lead or gold shielding and blast right through, there's a wee problem.
In contrast, the device mentioned in the article produces alpha particles (when configured appropriately, using Boron fuel). Alpha particles, if they touch metals, suck off 2 electrons to become helium atoms. This produces a net charge, and voila - electricity. The use of alpha particles in this way (such as from radioactive decay of certain isotopes) is well-tested. Since the majority (perhaps 95%) of the energy produced would be in the form of alpha particles, this type of reactor has the potential to be extremely efficient.
Regrettably, I don't have the background to determine whether it's all a crock or not. It sounds plausible, but all the best ones do. I'll believe it when it's powering my computer, but I'd donate a dollar to see if it could be done.
High-speed Road Trip (18.000KPH)
I can see the [H]ard forums now...
"Check out my new case mod! My PC powers itself!"
If the stable one-atmosphere plasmoid didn't do it, and the DIY breeder reactor didn't succeed, there will no doubt be some ingenious /. readers who decide to create a high-energy neutron source out in their garage to remove themselves from the gene pool. CmdrTaco, Timothy, what is it with all the sterility how-to guides you're giving your readers?
Get off my virtual lawn, you damned virtual kids!
Imagine all the little kiddies with their noses practically against the screen, getting dosed with ionizing radiation all the while. Or sitting in front of it, knees up, gonads up close and unshielded. One wonders if there would be identifiable effects from this... no time to check.
Scientists restrict study to entire physical universe; creationist
Put down the remote and step away from the tee vee, Sparky.
Damn, I hate these holiday "Star Trek" marathons.
I write in my journal
They're allways out of flux capacitors when I call, they say they'll be getting some in about two weeks, but they never come.
"Sic Semper Tyrannosaurus Rex."
The current state of fusion energy is pretty bad (way below a self-sustaining reaction) but this could still be used as a neutron source to drive a sub-critical fusion-fission reactor. Anyone who opposes fission power because of the spent-fuel issue wouldn't find this to be an improvement. (I would, because high-energy neutrons would be useful for transmuting fission products themselves, extracting their remnant energy and transforming them into stable isotopes. But I'm a geek and a technophile.)
Scientists restrict study to entire physical universe; creationist
But don't tell anyone I own a book of matches, okay?
Scientists restrict study to entire physical universe; creationist
Did you ever see the Simpsons where Homer and Grandpa went back to the old family farm, and homers shadow was burned into the wall from their Radiation King tv set. I also remember in 6th grade all the monitors in the computer lab had stickers on them, "Now With Low Radiation!", or something like that.
"Sic Semper Tyrannosaurus Rex."
Trekie... Believe it or not, but Star Trek wouldn't be considered your first rate Scientific Encyclopedia/
A Good Troll is better than a Bad Human.
Really? They seem in now ;-)
Get some real information on fusion:
European Community, Fusion Programme
U.S. Fusion Energy Sciences Program
International Thermonuclear Experimental Reactor or (ITER) site
a special Canadian ITER site
This page has a lot of links to different fusion sites around the world. These websites probably contain a lot more useful information than the slashdotted article.
By the way, my university happends to have a research center on plasma physics. It's not as easy as "some basic engineering skills, this site and the inspiration necessary to make your very own 'fusor' produce more energy than it consumes" =)
I read through some of the basic info on the page (before some of it got Slashdotted) and then started reading the forums. That's when I started finding the unfortunate schwag like this thread . The problem with all of these sorts of projects is that they tend to attract nutters who think they've rewritten the laws of physics in their garage from scratch using "maths" that they just can't divulge yet because they don't quite work. Ugh. Free energy weirdos and neuvo-quantum threory weirdos - two of a kind.
Things like this always make me wonder, if an area is so promising, why aren't there any academics out there getting funding to pursue it? I mean, I realize sometimes the academic ESTABLISHMENT can be closeminded, but if something has merit, there are usually a FEW academics who will go out on a limb and pursue it to the point that they demonstrate sufficiently interesting results to build a broader base of interest. I've never honestly heard of massive numbers of academics whole-hog ignoring truly promising areas out of some misguided conspiracy bullshit, and frankly it's quite hard to imagine, since the drive for personal fame and glory usually trumps the desire to avoid stepping on toes and to "toe the line".
It sounds like there is real work yet to be done to get these things close to breakeven, and it probably ain't gonna get done in some garage project, but hey, you never know.
its not like /. readers breed anyway.
"Sic Semper Tyrannosaurus Rex."
Unfortunately, the majority of the energy created in the system (which I think could plausibly break even or even function as a reactor, but if it were constructed to the highest precision, perfect sphericity, which we can not really obtain) is not in what particle is created, but the speed that particle is given due to the reaction. That's right, most of the energy from mass-energy conservation equation (E=M*C^2) is in the kinetic energy of the particles which have reacted. So using their electrical properties to evolve electrical energy is ignoring the vast majority of the energy.
Most generators (as far as I know) would convert this kinetic energy into thermal energy by using the velocity of the particles to heat some sort of water resorvoir, which would generate steam and drive a turbine like any old coal generator, except without the fire and coal and soot and yuck.
-Leo
Yeh. Too bad that the energy required to make a gram of anti-matter costs $20 trillion USD, takes 300 years to produce, and could provide enough electricity to light NYC for about 10 minutes.
AM/M reactors are prized for their energy density, not energy economy. Not to mention, that unless someone comes up with some sort of anti-matter breeder reactor, we'll never be able to make enough fuel to do more than experiment.
Now, being God, whenever I want anti-matter, I just re-adjust supersymetry temporarily, but lame fuckwads like you have to get your own. Nyah nyah nyah nyah!
PS. Zero-point energy is actually the holy grail, duh. Can't wait til next weeks slashdot article "You too can exploit the Casimir Effect!".
If it produces neutrons, some of those neutrons will escape, get captured, and produce radioactive waste. It may or may not be as bad as fission, but it's still a problem.
energy.
The second law is about entropy. Do you know what entropy *is*? Entropy is the law that requires heat engines to consume fuel despite conservation of energy -- and the single most misunderstood law of physics. Parent poster was right.
KFG
"This perpetual motion machine Lisa built is broken. It just keeps going faster and faster."
KFG
So I read through the patent and I've seen talks on electrostatic confinement fusion at plasma physics conferences (plasma physics is once again my day job).
...
... legalese is not good science writing) why high energy ions would be trapped and fuse in such a modest potential well.
I'm quite doubtful. My objection can be explained by looking at Figure 2 of the Hirsch and Meeks patent linked to through the fusor.net site.
You need accelerate the ions to high energy (or equivalently heat the ions to high temperatures) so that they will collide and fuse. If the energy is too low, electrostatic repulsion will prevent the nuclei from getting close enough to let the strong force do its work.
So what is my objection with Figure 2?
To confine a plasma with sufficient energy to have respectable amounts of fusion requires very high potentials (think many mega-volt DC potentials) to trap the ions if you are doing it electrostatically. If the potential barrier isn't high enough, the ions will escape the reactor without fusing---you dump all this energy into the ions and they just leave, taking your energy with them
For an electrostatic confinement system, you would need confining potentials comparable to the height of the nuclear electrostatic repulsion barrier (for the ions to fuse, they need to have energies higher than the nuclear electrostatic repulsion barrier but below the reactor electrostatic confinement barrier).
Figure 2 is the potential distribution for the reactor. The potentials are a couple _thousand_ times too small to have any chance of confining fusion capable ions. At no point in the patent was it explained (clearly
Kevin
P.S. Furthermore, a purely electrostatic confining potential is not allowed by Poisson's equation (the equation governing electrostatics), as is taught in any first year college physics class. The quick explanation is that Gauss's law implies the existance of a charge in the potential well. But if you are trying to make a trap to isolate a particle, that is exactly what you don't want in your well. For example, Penning traps use a combination of electrostatic confinement (confinement at the end-caps) and magnetic fields (radial confinement). However, I'll give them the benefit of the doubt as this appears to be relying on dynamic effects virtual cathode/anode effects. (Actually, much of the initial modeling of virtual cathodes was done by my thesis advisor in the 1960s.)
The site recommends an article from tom ligon on Analog magazine, which talks about "the simplest fusion reactor". /.ed but over free bandwidth.
Since all you slashdot readers are kinda lazy here is the google cache for the article:
link
Its pretty nice, since the tripod page linked on the site is not
My english is sow-sow. Sowhat?
Gone Fission
Then you'd be in trouble.
There are really lots of people who helped create TV as we know it.
autopr0n is like, down and stuff.
The truth is that wind power is all we need, and perhaps all we will have in just 30 years.
Well ... mistaking the natural background neutron flux for fusion has been a recurring theme in exotic fusion research. (A recent example is the controversy over claims by Oak Ridge scientists that miniscule amounts of fusion were being produced by sonoluminescene.)
...
I have no doubt that you can make a glowing ball of plasma with this technique. It wouldn't rock my world if there was an infinitesimal amount of fusion going on. But, I don't see any reason to believe this will be the next generation power source or could be developed into one.
This isn't an out of hand dismissal of the exotic techniques; I'm much more open to wacky ideas than many of my colleagues. And I don't have a whole lot of faith in mainstream techniques for fusion becoming viable power sources either (but that is another issue).
However, the mainstream techniques have calculated the requirements needed to make a viable fusion reactor. It is neatly summarized by the Lawson criteria. By looking at Lawson criteria, you can develop different strategies for designing a fusion reactor. The strategies amount to trade offs between plasma density, plasma temperature or duration of confinement. Laser and heavy-ion inertial confinement aim for high-density but short confinement time. Magnetic confinement uses a long confinement time but a low density. And so forth
I don't see anything here to indicate this is competitive with mainstreams techniques (which are themselves already lacking) and there are obvious problems with the physics in making the reactor more practical.
But I could be wrong.
Kevin
The Farnsworth Image Dissector sensed the whole image at once, turning it into a collimated beam of electrons. But then it deflected the collimated beam over a scanning aperture, only using a tiny portion of the beam at a time. This approach is very insensitive. The incoming light energy is divided by the number of pixels. Image dissectors thus only work with brighly lit scenes. Very brightly lit scenes. Even with a big lens, you needed bright sunlight. Early versions were hopeless, but by adding some photomultiplier stages, Farnsworth managed to increase the sensitivity a bit. But it was still lousy. Image dissectors are still used today for looking into furnaces, but not for much else.
Zworklin's Iconoscope, on the other hand, accumulated light over a whole frame time, and scanned it off a photosensitive plate with a scanning electron beam. Iconoscopes didn't have a photomultiplier stage, and they, too, produced a weak signal.
After much litigation, licensing, and years of work, RCA Labs finally produced the image orthicon, a complex and expensive tube that combined the photosensitive plate of the iconoscope with the photomultiplier stages of the image dissector. This, at last, produced a usable TV camera tube.
Uhhh... fission means spliting atoms, fusion means combining them together. A fission reactor would be both more dangerous and less new worthy because we've already been there done that.
...And people fuse atoms all the time, it's just that they've never been able to set up a sustainable reactor.
Why, o why must the sky fall when I've learned to fly?
I'm not sure you understand the meaning of "ad hominmen". The question was a legitmate one. The link you provided supported my argument that IEC is not a power supply as claimed by the slashdot summary.
In your original post, you quote a fusion rate, that while still miniscule, is a thousand times higher than what is actually claimed by your own link:
"Clearly, the fact that these systems produce neutrons in substantial quantities seems unassailable - whether the exact results or numbers Hirsch and Meeks reported or claims (billions of neutrons per second or whatever)"
So, do you read your own links?
Kevin
I spent about an hour reading through the whole fusor.net site, including many of the forum posts, prior to posting anything, though clearly you did not or you would realize that the operators of that site made no such claim that you are arguing against. The results of the U Wisconsin group are ~1E8 neutrons/sec and the portable commercial device I linked to here are ~1E7. Please don't be a fucknut and imply that somebody with half a brain can't properly compare orders of magnitude. So again, cut the fucking ad hominem attacks ("Do you read your own links?"). That is an offensive comment to make as it implies that I have somehow made some whopping error in logic or observation, which I have certainly not done. The only error of logic and observation being made here is by you, who seems to want to attribute to me your own misreading of a fucking moronic Slashdor editor/submitter, which I had fuck-all to do with.
inventor, Philo T. Farnsworth
Any relation to Hubert Farnsworth, inventor of the Smell-o-Scope, the Fing-Longer, and the Death Clock?
"Defenestration" is to throw out of a window; what's a word for throwing 'Windows' out of something?
images can be found here.
basicly what is created is the center of a star or planet. The physical spheres are used to focus energies which create the necessary field structures to contain one another and they then force further contraction until their own "gravity" causes them to fuse.
I do belive the latest theory of why the earth gives off heat is due to a sustained fusion reaction in the center of the planet. Could this be just the proof of such a posibility?
comment directly in my journal
If you look at the the general tenor of comments about the story and the submitter of the story, they are talking about a fusion power supply---not a low flux isotropic radiographic neutron source. My original comment was directed at them and I stand by it.
Your original reply to the my post was hostile, implied I didn't know my butt from a hole in the ground (that remains to be seen), that I was implicitly accusing researchers of scientific fraud. So, don't be too surprised when you get a curt response.
Kevin
Dr. Mitchell Swartz, who publishes the Cold Fusion Times, is able to procure and distribute heavy water for about $15/liter plus shipping and handling, I believe.
Perhaps you are familiar with the Altamont Pass wind generators, which are quite noisy. Modern wind turbines are quiet (but not so quiet that birds can't hear them) and are generally not resisted by NIMBY-types, even in comparison to ordinary electrical wires. They coexist well with ordinary farmland, and probide the farmers with an extra source of income; in many cases exceeding that of their income from the crops and/or livestock on the same land. Free money makes the backyard wind turbine much more attractive.
This is a myth. Birds have been naturally selected for hundreds of millions of years for their ability to avoid objects while flying. The many wind turbines already in California pose no significant risk to condors or any other endangered species. They do kill a few raptors now an then, but not even 1% of enough to impact their population.
Funny you should mention that. As a former student at the LSU Nuclear Science Center, I can tell you that cold fusion was investigated without results. People there spent time, energy and money to try to reproduce cold fusion but never saw any neutrons. It just goes to show that people will look into things.
I'm not sure they ever did anything with this kind of "fuser." They had a linear accelerator which they used for fusion and other experiments. I don't know what kind of flux they got out of it nor do I know if anyone there worked on any other kind of fusion. They have an impressive collection of thesis and disertations hanging around the building.
Friends don't help friends install M$ junk.
I still want fusion though, badly. The promises and possibilities are too great to ignore. Fusion would give us power to burn, and could make ideas that are impractical now a reality.
"A language that doesn't affect the way you think about programming, is not worth knowing" - Alan Perlis
We do not live in the 21st century. We live in the 20 second century.
most of the energy... is in the kinetic energy of the particles which have reacted. So using their electrical properties to evolve electrical energy is ignoring the vast majority of the energy.
You must have missed or missunderstood their method of capturing the energy because they ARE capturing that energy.
The Alpha particle flies out from the center with a +2 charge and huge kinetic energy. As it leaves the center it climbs against a 3 megavolt potential. This slows the alpha particle to nearly zero speed and zero kinetic energy. The minetic energy has been nearly perfectly converted into electrical potential. It then grabs 2 electons. Each of those 2 electrons is at a 3 megavolt potential. That one alpha particle just gave you 6 million electron-volts of energy. Kinetic energy is captured with amazing efficency.
Actually it's a little more complicated than that because each reaction also produces 2 other alpha particles at different energies, but the principle is the same for them.
-
- - You can't take something off the Internet! That's like trying to take pee out of a swimming pool.
Kids getting arrested for science fair projects that frighten the principal are too common.
This kid had to hire a lawyer to get his suspension redacted from his permanent record.
He said he was going to build a Plastic Hydrogen Bomb from plans on the Internet, and that his parents were buying him the parts. The principal had his house searched by the police.
The plans were included in the police report.
Free book: Science Toys You Can Make
Here's a link [eads.net] to Arianspace's commercial product (a lab tool, not a positive power fusion reactor) which generates a useful neutron flux based on these IEC techniques.
Given this, presumably there can be no more discussion as to whether IEC produces fusion (although alternative mechanisms are always a possibility). Scaling up is the real question now.
"The question of whether machines can think is no more interesting than [] whether submarines can swim" - Dijkstra
they come up with a thing to power my laptop. Propelling rockets, my ass. We need this for laptops, remote controls and cordless mice. I dont give a damn about fusion unless they can put it in a AAA cell.
The two most prominent links to IEC-based fusion technology seem to be Arianespace's FusionStar FS-NG1 Neutron Generator and the Advanced Fuels Project at University of Wisconsin-Madison.
:-)
These pretty much place fusion by IEC techniques on solid ground. Now we "just" need to focus on issues of scaling up to positive-power systems.
"The question of whether machines can think is no more interesting than [] whether submarines can swim" - Dijkstra
Perhaps because you can't fit a fusion reactor in a vehicle smaller than a large ship? There's an irreducible amount of shielding you need for even the cleanest fusion fuels. And making synfuels with fusion is simply noncompetitive.
What does God need with anti-matter?
-- El Sacarino tiene gusto de la chocha
I eat it on hot dogs, along with mustard and relish.
Duh.
The really important question is, what sort of reaction could breed more anti-matter than it consumed... and could you ever risk experimenting with it? That's the question you should have asked.
The Sun produces all the energy we will ever need, tends itself and has fuel enough to last for billions of years.
Instead of spending tens of billions of dollars in order to recreate the process here on Earth, we should spend most of the money trying to harness the energy of the giant fusion reactor kindly provided to us by Nature.
That's not to say we shouldn't strive to understand the process(es) of fusion, so we do need the research, but our energy needs are already met.
And remember kids: Never trust a computer you can actually lift.
There's been some work on inertial confinement fusion done at university of Illinois... I'm too lazy to google for any names right now.
IEC is very promising for space propulsion. Tokomaks are way to heavy to carry on board your spaceship.
There are 10 types of people in this world, those who can count in binary and those who can't.
For all but one successful (meaningful) fusion reactor you do need uranium. Of course all (but one) of are fusion reactors are hydrogen bombs, which are basically an atom bomb with (heavy) water inside.
;-) ) (btw, you have about 2 hours from the start of the exposure before ... well let's just say you want the experiment to be finished by then)
This way you describe to make a fusion bomb is completely wrong. Not even close.
->get 2x7,5 kg of U-238 (weapons grade, obviously) (somewhat toxic, but don't swallow it and you'll live to see the end of the experiment) (not the end of your natural life though
It's U-235 that's used for bombs! U-238 is not fissionable at all.
->make a hole in the uranium (in the middle) and put in the water balloon
->smash the two pieces together as hard as you can (doesn't need to be all that hard actually, but it might require two tries)
You can't induce fission by banging uranium together! Where the hell did you come up with that! It's hard to induce fission. You need immense pressures. The fissionable material in Little Boy wasn't surrounded by high explosives just for the hell of it.
this will create a thermonuclear explosion which will blow around the water balloon, heating a tiny bit of water over the threshold of the "strong force" (sorry I don't know the correct translation) and compress it. It will convert a few micrograms of water into energy. This will blow up something between 10 and 100 square kilometers around you.
Thermonuclear explosion is fusion, not fission. You got that one wrong. Also, you can't just fuse water. Doesn't work that way. Unless you have the temperatures and pressures akin to the core of the sun. You need deuterium and tritium, typically, although other things can fuse.
If you don't understand any of my sayings, come to me in private and I shall take you in my German mouth.
Maybe I've missed the point and the fusion part of IEC isn't relevant to IEC as a propulsion system. If so, why use IEC as opposed to VASIMR, MPD, Hall thrusters, ...
... needless to say, but it would be very difficult to make this work.)
I've seen some talks on IEC as a propulsion source. (I've seen similar talks about using distorted Tokamaks and the Spheromaks.) It's not out of the question but there are lots of means of accelerating your propellant once you've made the decision that chemical rockets aren't going to cut it.
Once you've moved away from chemical propellants, one of the big questions is: where are you going to get your power for the propulsion system? For a chemical rocket, the energy is largely liberated from the reactants themselves.
If IEC isn't going to give you the energy from fusion, then you still have to carry the weight of some other power source. The talks I've seen proposing IEC as a propulsion source assume the propulsion power would be generated from the fusion reactions themselves (and the IEC produces directed propellant flow by using electrodes distorted from their gridded spherical shape).
However, IEC's fusion yield, for reasons discussed at length previously, is presently infinitesimal. So, if you want to use IEC as a propulsion device, you still need to lug around some other power supply. In such a configuration it isn't clear that IEC is competitive with any of the other advanced propulsion schemes out there.
If you could get IEC's fusion yield up several orders of magnitude, IEC could be a promising fusion based propellant system.
Kevin
P.S. I'm not clear what you are considering as the propellant. If the fusion products are the propellent (which would be nice as the fusion reaction liberate energy), then choice of fusion fuel is very important; I doubt you can make fast neutrons a useful propellant. However, if you are just planning to use the energy liberated from IEC fusion reactions to heat your propellant, then IEC is really just acting as a power supply. (Possibly a compact one though if the unreacted fusion fuel and the propellant are one and the same---using the fusion energy to heat the plasma for thrust purposes
On the contrary, those are offshore.
The unsubsidized cost of wind power is about nine cents per kilowatt hour. That makes it competitive with almost everything except coal, including natural gas.
Electrolysis, a method of generating hydrogen fuel from water and electricity, can be done at nearly any scale, to provide round-the-clock availability.Electrolysis is grossly noncompetitive as a source of hydrogen. Even hydrogen from biomass is cheaper if the the cost of electricity is greater than 2 cents/kWh.
True, but with continental wind grids, virtually none is needed. The wind is always blowing somewhere, even at night.
I suspect that wind-electrolyzed hydrogen will become financially relevant before 2009. By that time, the scale of mass production of turbines will have rendered them less as expensive than a few dozen streetlamps, pushing the cost of their power down to direct competition with coal.
Fossil fuels are not renewable; therefore, that statement will only be true for a finite time. Who knows how long?
Electrolytic hydrogen production is already in use commercially.
IEC Fusion offers very high thrust to weight levels and very high Isps... some estmates I've read give thrust to wieght of abut 30x and Isps from 5000-15000. Obviously such engines haven't been developed yet or else i'd be writing this from Mars right now :)
Tokomak type fusion will not be good for propulsion unless some sort of materials breakthrough significantly reduces the weight of the confinement apperatus. Such engines seem viable only for battlestar galactica type spacecraft.
Hall thrusters are low thrust only... I looked up VASIMR, but I can't find anything estimating thrust levels or Isp. VASIMR looks like a scheme to get higher thrust levels out of a Hall thruster... however, I doubt that such a device could be constructed out of any materials available on the near horizon... and it looks heavy with all of the magnets... but like I said, I couldn't find any estimtes of Isp or T/W.
Once you've moved away from chemical propellants, one of the big questions is: where are you going to get your power for the propulsion system? For a chemical rocket, the energy is largely liberated from the reactants themselves.
And the best you'll get out of a chemical system is maybe 400 secs of Isp... and that will be with very dangerous and very toxic propellent. If you use a low molecular weight fuel like hydrogen and provide energy to it from another source you can get much, much higher Isps (800-30000 sec). The power can be from solar thermal, solar electric, beamed energy, nuclear fission, nuclear fusion, antimatter, etc.
I think an IEC fusion device might be able to be combined synegistically with a fusion device to provide very, very hot hydrogen... without the radioactive exhaust of nuclear-thermal rockets like NIRVA. And if an IEC fusion device could produce a breakeven fusion reaction, then it will be a much better choice for a fusion engine than a tokomak.
There are 10 types of people in this world, those who can count in binary and those who can't.
Here's some info on VASIMR that estimates Isp of 30,000... it gives some thrust info but I didn't find the system weight info in my quick glance through this so I couldn't really attach meaning to the thrust numbers... anyway here's the link:
n .p df
http://dma.ing.uniroma1.it/users/bruno/Petro.pr
Anyway, the technically feasiblity or infeasibility of systems such as VASIMR isn't really relevent to my original point that IEC fusion systems are very promising in their potential uses as propulsion systems.
Yeah, these systems need really high electric field densities, but every advanced technology has kinks to work out or else someone would have built them by now.
There are 10 types of people in this world, those who can count in binary and those who can't.
True. That energy is captured by the electric field however. The particle's origination point is known, and its energy (kinetic) is known from the reaction which produces it. This lets you calibrate the electric field so that it saps the majority of the particle's kinetic energy, leaving it just enough to barely touch the walls of the reaction chamber and suck off some electrons. You're not actually wasting the kinetic energy.
High-speed Road Trip (18.000KPH)
Electrolytic hydrogen is a tiny fraction of current hydrogen production. It's used when thermochemical hydrogen isn't available (for example, in spacecraft, or in very small scale applications where the thermochemical plant doesn't scale down well). On an economy-wide scale it would not be competitive.
That may be true for traditional electrolysis, but proton-exchange membranes are very much like fuel cells "running in reverse," and much more efficient.
Proton Energy claims that medium-scale hydrogen storage of electric power costs 250% of input costs due to the inefficencies. If you have a isolated wind grid that needs to use hydrogen-stored electricity 20% of the time due to calm winds, that means you are paying 160%, or about 14.4 cents per kilowatt hour, just a little more than natural gas, and at about seven cents less than California's famous long-term contracts signed at the height of the manufactured "energy crisis."
Natural gas to large customers is a hell of a lot cheaper than 14.4 cents per kWh. Electrolysis might make sense for niche applications, like off-grid, but for the economy as a whole it's a non-starter.
Thanks