..but as of yet, the experimental evidence seems to be promising
What evidence? The published results have been nonexistent to no positive results. In fact all the current results show that the rest of the physics community is correct. There is also quite a bit of data on this sort of thing, its not as new as some think.
, and the Navy continues to fund it.
They also funded cold fusion. The navy giving funding to something is not a vote of scientific merit.
Dr. Nebel is responsible for continuing Dr. Bussard's Polywell research, and has made it clear that there are no show stoppers thus far.
And is there any published data? Any published papers? Anything other than a media PR press release?
Anyway, the electron scattering and xray losses turn out to be considerably less than one would expect in the Polywell.
Well all the data on this i have seen does not suggest this at all. In fact the losses look about right from theory. Massively higher than the fusion yield.
Furthermore, it is not a thermal system, so much of the conventional wisdom does not apply.
Got anything other than an assertion to back that up. Because I have data, and some pretty well tested theory that says this is not the case.
It isn't that entropy needs to go away, but it doesn't play a big part at the timescales in question. (ie. it doesn't thermalize quickly enough to matter, and there may even be a mechanism which prevents it from thermalizing.)
Since fusion requires a *collision*, and thermalizing is via *collisions* this is quite false. You can't change the fact that the probability of scattering is *much* higher than the probability of fusion. This means that thermalization is the faster process.
I'm not sure what experimental counter evidence you are referring to, as this is a rather unique system which has not been studied elsewhere. It is also a computationally intractable problem, so there are no shortcuts in this case.
Both statements are incorrect in any practical sense. First the Russians have worked on this stuff. Buzzards original paper even cites them. They developed the idea of virtual electrodes in a plasma. Also the system is as far as collision process are concerned, similar to other electrostatic confinement methods. They get fusion easily, but fail at anything other than a neutron source.
The polywell is quite tractable numerically in any practical sense. If its not, where are all the predictions coming from? We can simulate tokamaks with some degree of success. The plasma parameters of a polywell make it easier, not harder.
Fission is a dead end with the seemingly insoluble issue of nuclear waste.
Not true. There are ways to deal with the waste, but they involve reprocessing in one way or another and generally fast reactors. These are *poltical* problematic. With a fast reactor and transmutation, you could have the pretty small amount of waste (a few tons per GW per year) safe in just 100 years or so. Considering that the church down the road is 400 years old, this is practical technically. There are other options.
But speaking as a physicist you state that the polywell is doomed?
The vast majority of physicists agree with me (even the physicists that think AGW is bunk). A huge number of experiments agree with me (The Russians worked on this a long time ago). The theory that matches the experiments agrees with me. It not that fusion can't work. Its that the polywell in its current incarnation can't work.
Now add the fact that the published results from the polywell don't even get close to matching the claims of proponents. In fact home made fusors have got far better neutron yields.
And would you say that it is as doomed as the Tokamak?
A tokamak can at least work in theory. A polywell can't. Polywell proponents refuse to even acknowledge all this theory and experimental data let along demonstrate how it is not applicable to a polywell.
Furthermore, the US military is already funding polywell technology..
They have also funded cold fusion, and some quite bizarre and sometimes stupid things. US military funding is not an indication of scientific merit.
Why make a requirement at all? Why not teach what needs to be taught in a "technology agnostic" manner and let the students use whatever tools they see fit to use.
The price of solar is about 4.12EU per watt. So 1GW of cells will cost about 4.12 billion euros. These prices are not for high efficiency modules (ie about 15%) but lets assume we can get 20% efficiency. That's about 150 watts per m^2 at *mid day*. This requires a square about 2.5km on each side for 1GW, and then it only does that when the sun is high. The average is much much lower. And the true size would be much larger (gaps between modules). So installing the 4 billon euros worth of cells over a block of land about 3km a side, with all the wiring required is going to cost a lot. A lot more that the cell price of 4 billion. And your average power output is *below* 500MW and you can't control *when* you get the power.
I all adds up to "do you want to pay 3-5x for electricity?".
On your last point. It may well be possible to have the low grade waste caused by neutron activation to have a much shorter total half life. Perhaps even so low that is safe after just 100 years. This is because you only need to pick materials with low neutron activation and you don't care about neutron economics as with a fission reactor. This makes the list of materials you can choose from much larger apparently, and hence much easier to optimize.
Because it illustrates the problem perfectly. One *person* claims that the worlds problems are caused by all the people. When in reality they believe the worlds problems are caused by all the *other people*.
If someone really thinks genocide is the solution, you better be first in line. Otherwise you are a hypocrite.
I am a physicist. Out of that list the only one that doesn't need a pretty enormous piece of magic is option 2. In fact its the best bet for a fusion dark horse out there. It requires no magic, other than a stable plasma (harder than it looks).
Polywell needs entropy to go away. The probability of scattering is *much* higher than fusing, hence you need to pump in more energy than you get out. You can arm wave all you like. There is a lot of *experimentally* verified theory to back up that it won't work. The assumption that it will, would require that a *lot* of different experiments to get completely different results (and to still be getting different results).
The same experimentally verified theory that dooms polywell, also dooms colliding beam fusion. Again we would see vastly different results from many different experiments over the years if it would even be within an order of magnitude of working. The probability of scattering is still much higher than the probability of fusion. It is just a fact of nature. The probability of fusion is really low.
Note that you don't even need to go into xray losses to show that the previous options can't work. But xray losses make the problem totally untenable. And if you want the device to be smaller than a planet, you are going to need elections around hot ions. The hot ions will heat the electrons and you will get xray losses. Run the numbers and it looks pretty bad for all currently proposed exotic fusion devices. Many people who like the exotic options just pretend that these results don't apply, without any justification or experimental data. It doesn't work that way.
The Dense Plasma Focus is interesting. If they would stick with DT fusion or even DD fusion they have a fighting chance and no magic would be required. However he keeps pushed B-p fusion in a thermal plasma. And to suppress the xray losses you need mega-Tesla fields. That a bit of magic. However the issues is not just ignored or sweep under the carpet like proponents of other devices. He does know about it and is theoretically trying work the problem.
The good news is that he is testing with DD first. If you can do B-p, DD fusion is easy by comparison, and would be the energy breakthrough of our age. If you can do DD fusion you can do DT even easier and with much higher power density. It would be all gold. This is dark horse option number 2.
Personally its crazy that we rant on about the future with global warming and stuff. Talk about multi-billion dollar carbon credits, bail out failed banks to the tune of hundreds of billions, and then can't fund a 20 year project 20-40billion over the *lifetime* of the project.
And yes, i propose we have serious money going into both fusion and fission research *now*, so we have options to choose from later.
I am using the 64bit flash on my linux's boxes and have very good stability. My wife is addicted to flash games and facebook. My daughter will watch 3 different youtube videos with facebook games etc are on other tabs. So it gets properly tested. Not only are my systems still very responsive, but i don't get crashes or lockups either.
Ok that's not quite true. Firefox has a very slow memory leak, and it needs to be restarted about once a month. That could be caused by the flash plugin i guess.
I liked doom the movie. I even brought the DVD. But then i was expecting a movie with all the plot of well Doom.
I loved playing Doom and Doom II, but lets face it, there was zero plot, and still to this day its the kind of FPS i love. Shoot to kill *everything*. Doom3 was not a plot improvement, but dam scary. My wife and daughter would sneak into my office and go boo--which would totally freak me out. My brother didn't even finished Doom 3, since he found it too tense and too scary.
The movie was more of "doom 3" thriller style than the kill em' all of the previous 2, but thats was ok. As for plot. Well you know it was fine. I always say that if you want a plot, read a book and leave Hollywood out of it. Think of movies that get lots of positive reviews, like wall-e or up. How is these "plots" more of a plot. They are not.
Sure doom the movie was no Shaw Shank Redemption nor a Schindler's list. But it *was* a doom movie, and i liked it for that reason. For the same reason i like the Resident evil movies, a pretty stock standard zombie flick. I like zombie movies.
I have said this before. I worked for ISPs in NZ, I have friends working for ISPs in NZ now. There are other cables. At least one to the US and at least one in the general direction of Japan(don't remember where is goes exactly anymore). I also worked for telecom for a while. The cost of bandwidth on any of these cables is so low (cents per 100Gb), that bandwidth caps have more to do with telecom than any other single factor.
Telecos may not tell you this. But there are more than that cable servicing NZ international bandwidth. There is at least one going to the west cost of USA and one heading up to japan. They installed the latest pacific cable while i was still living in NZ, with the cable work on one of the beaches in Auckland making the news papers. A new cable like that has serious capacity.
Fact is, most of the "bandwidth caps" and costs have more to do with artificial scarcity and cheaper local infrastructure. As an example I could regularly get +10Mbit to USA at Auckland University pretty much any time of day and often more than 50Mbit. That about as good as i get to USA from here (EU).
Telecom like to give good deals to xtra. An ISP that is a telecom subsidiary. The rest pay full price. I have friends working in NZ ISP's (I did myself at one point) and what goes on behind the curtain is pretty insane. NZ Telecom is so blatantly anti competitive at an illegal level its a total joke. And the consumer watch dog does SFA. Its also difficult to raise the issues legally as telecom will have "technical issues" with your adsl customers, and you go out of business before anything gets done.
What wrong is that it doesn't matter if your browser supports all the features. It only matters that the browser identifies as safari/mac. The explanations are either incompetence or malice. I suspect both.
Slashdot Mirror
Since every stockbroker is using the *same* software, guess what they short and sell.
..but as of yet, the experimental evidence seems to be promising
What evidence? The published results have been nonexistent to no positive results. In fact all the current results show that the rest of the physics community is correct. There is also quite a bit of data on this sort of thing, its not as new as some think.
, and the Navy continues to fund it.
They also funded cold fusion. The navy giving funding to something is not a vote of scientific merit.
Dr. Nebel is responsible for continuing Dr. Bussard's Polywell research, and has made it clear that there are no show stoppers thus far.
And is there any published data? Any published papers? Anything other than a media PR press release?
Anyway, the electron scattering and xray losses turn out to be considerably less than one would expect in the Polywell.
Well all the data on this i have seen does not suggest this at all. In fact the losses look about right from theory. Massively higher than the fusion yield.
Furthermore, it is not a thermal system, so much of the conventional wisdom does not apply.
Got anything other than an assertion to back that up. Because I have data, and some pretty well tested theory that says this is not the case.
It isn't that entropy needs to go away, but it doesn't play a big part at the timescales in question. (ie. it doesn't thermalize quickly enough to matter, and there may even be a mechanism which prevents it from thermalizing.)
Since fusion requires a *collision*, and thermalizing is via *collisions* this is quite false. You can't change the fact that the probability of scattering is *much* higher than the probability of fusion. This means that thermalization is the faster process.
I'm not sure what experimental counter evidence you are referring to, as this is a rather unique system which has not been studied elsewhere. It is also a computationally intractable problem, so there are no shortcuts in this case.
Both statements are incorrect in any practical sense. First the Russians have worked on this stuff. Buzzards original paper even cites them. They developed the idea of virtual electrodes in a plasma. Also the system is as far as collision process are concerned, similar to other electrostatic confinement methods. They get fusion easily, but fail at anything other than a neutron source.
The polywell is quite tractable numerically in any practical sense. If its not, where are all the predictions coming from? We can simulate tokamaks with some degree of success. The plasma parameters of a polywell make it easier, not harder.
Fission is a dead end with the seemingly insoluble issue of nuclear waste.
Not true. There are ways to deal with the waste, but they involve reprocessing in one way or another and generally fast reactors. These are *poltical* problematic. With a fast reactor and transmutation, you could have the pretty small amount of waste (a few tons per GW per year) safe in just 100 years or so. Considering that the church down the road is 400 years old, this is practical technically. There are other options.
But speaking as a physicist you state that the polywell is doomed?
The vast majority of physicists agree with me (even the physicists that think AGW is bunk). A huge number of experiments agree with me (The Russians worked on this a long time ago). The theory that matches the experiments agrees with me. It not that fusion can't work. Its that the polywell in its current incarnation can't work.
Now add the fact that the published results from the polywell don't even get close to matching the claims of proponents. In fact home made fusors have got far better neutron yields.
And would you say that it is as doomed as the Tokamak?
A tokamak can at least work in theory. A polywell can't. Polywell proponents refuse to even acknowledge all this theory and experimental data let along demonstrate how it is not applicable to a polywell.
Furthermore, the US military is already funding polywell technology..
They have also funded cold fusion, and some quite bizarre and sometimes stupid things. US military funding is not an indication of scientific merit.
Why make a requirement at all? Why not teach what needs to be taught in a "technology agnostic" manner and let the students use whatever tools they see fit to use.
The price of solar is about 4.12EU per watt. So 1GW of cells will cost about 4.12 billion euros. These prices are not for high efficiency modules (ie about 15%) but lets assume we can get 20% efficiency. That's about 150 watts per m^2 at *mid day*. This requires a square about 2.5km on each side for 1GW, and then it only does that when the sun is high. The average is much much lower. And the true size would be much larger (gaps between modules). So installing the 4 billon euros worth of cells over a block of land about 3km a side, with all the wiring required is going to cost a lot. A lot more that the cell price of 4 billion. And your average power output is *below* 500MW and you can't control *when* you get the power.
I all adds up to "do you want to pay 3-5x for electricity?".
20billion for a research reactor is cheap.
And even with the wrong numbers, its still cheaper than the banking sector.
On your last point. It may well be possible to have the low grade waste caused by neutron activation to have a much shorter total half life. Perhaps even so low that is safe after just 100 years. This is because you only need to pick materials with low neutron activation and you don't care about neutron economics as with a fission reactor. This makes the list of materials you can choose from much larger apparently, and hence much easier to optimize.
Because it illustrates the problem perfectly. One *person* claims that the worlds problems are caused by all the people. When in reality they believe the worlds problems are caused by all the *other people*.
If someone really thinks genocide is the solution, you better be first in line. Otherwise you are a hypocrite.
I am a physicist. Out of that list the only one that doesn't need a pretty enormous piece of magic is option 2. In fact its the best bet for a fusion dark horse out there. It requires no magic, other than a stable plasma (harder than it looks).
Polywell needs entropy to go away. The probability of scattering is *much* higher than fusing, hence you need to pump in more energy than you get out. You can arm wave all you like. There is a lot of *experimentally* verified theory to back up that it won't work. The assumption that it will, would require that a *lot* of different experiments to get completely different results (and to still be getting different results).
The same experimentally verified theory that dooms polywell, also dooms colliding beam fusion. Again we would see vastly different results from many different experiments over the years if it would even be within an order of magnitude of working. The probability of scattering is still much higher than the probability of fusion. It is just a fact of nature. The probability of fusion is really low.
Note that you don't even need to go into xray losses to show that the previous options can't work. But xray losses make the problem totally untenable. And if you want the device to be smaller than a planet, you are going to need elections around hot ions. The hot ions will heat the electrons and you will get xray losses. Run the numbers and it looks pretty bad for all currently proposed exotic fusion devices. Many people who like the exotic options just pretend that these results don't apply, without any justification or experimental data. It doesn't work that way.
The Dense Plasma Focus is interesting. If they would stick with DT fusion or even DD fusion they have a fighting chance and no magic would be required. However he keeps pushed B-p fusion in a thermal plasma. And to suppress the xray losses you need mega-Tesla fields. That a bit of magic. However the issues is not just ignored or sweep under the carpet like proponents of other devices. He does know about it and is theoretically trying work the problem.
The good news is that he is testing with DD first. If you can do B-p, DD fusion is easy by comparison, and would be the energy breakthrough of our age. If you can do DD fusion you can do DT even easier and with much higher power density. It would be all gold. This is dark horse option number 2.
Personally its crazy that we rant on about the future with global warming and stuff. Talk about multi-billion dollar carbon credits, bail out failed banks to the tune of hundreds of billions, and then can't fund a 20 year project 20-40billion over the *lifetime* of the project.
And yes, i propose we have serious money going into both fusion and fission research *now*, so we have options to choose from later.
I am using the 64bit flash on my linux's boxes and have very good stability. My wife is addicted to flash games and facebook. My daughter will watch 3 different youtube videos with facebook games etc are on other tabs. So it gets properly tested. Not only are my systems still very responsive, but i don't get crashes or lockups either.
Ok that's not quite true. Firefox has a very slow memory leak, and it needs to be restarted about once a month. That could be caused by the flash plugin i guess.
Mirrors reflect light-light is momentum. You control the direction of the reflected light.
Detailed solar sail trajectories are around the internet. My favorite is the H-reversal sun flyby trajectory.
You mean like say DH, RSA and ECC?
You can't patent the way you drive your car....
Are you sure about that?
His Far cry movie was absolutely terrible. Well the first 20min was, which is as far as i got before turning it off.
I liked doom the movie. I even brought the DVD. But then i was expecting a movie with all the plot of well Doom.
I loved playing Doom and Doom II, but lets face it, there was zero plot, and still to this day its the kind of FPS i love. Shoot to kill *everything*. Doom3 was not a plot improvement, but dam scary. My wife and daughter would sneak into my office and go boo--which would totally freak me out. My brother didn't even finished Doom 3, since he found it too tense and too scary.
The movie was more of "doom 3" thriller style than the kill em' all of the previous 2, but thats was ok. As for plot. Well you know it was fine. I always say that if you want a plot, read a book and leave Hollywood out of it. Think of movies that get lots of positive reviews, like wall-e or up. How is these "plots" more of a plot. They are not.
Sure doom the movie was no Shaw Shank Redemption nor a Schindler's list. But it *was* a doom movie, and i liked it for that reason. For the same reason i like the Resident evil movies, a pretty stock standard zombie flick. I like zombie movies.
Most folks I know here have similar usage patterns. I don't know anyone that's using under 50G. The cake does not need to be a lie.
Google is your friend. Clue one. The southern cross cable *network* doesn't just go to Austria.
I have said this before. I worked for ISPs in NZ, I have friends working for ISPs in NZ now. There are other cables. At least one to the US and at least one in the general direction of Japan(don't remember where is goes exactly anymore). I also worked for telecom for a while. The cost of bandwidth on any of these cables is so low (cents per 100Gb), that bandwidth caps have more to do with telecom than any other single factor.
Telecos may not tell you this. But there are more than that cable servicing NZ international bandwidth. There is at least one going to the west cost of USA and one heading up to japan. They installed the latest pacific cable while i was still living in NZ, with the cable work on one of the beaches in Auckland making the news papers. A new cable like that has serious capacity.
Fact is, most of the "bandwidth caps" and costs have more to do with artificial scarcity and cheaper local infrastructure. As an example I could regularly get +10Mbit to USA at Auckland University pretty much any time of day and often more than 50Mbit. That about as good as i get to USA from here (EU).
I was using over 100gig per month on 2Mbit. I am now on 8Mbit... True unlimited is the way to go.
Telecom like to give good deals to xtra. An ISP that is a telecom subsidiary. The rest pay full price. I have friends working in NZ ISP's (I did myself at one point) and what goes on behind the curtain is pretty insane. NZ Telecom is so blatantly anti competitive at an illegal level its a total joke. And the consumer watch dog does SFA. Its also difficult to raise the issues legally as telecom will have "technical issues" with your adsl customers, and you go out of business before anything gets done.
I doesn't matter how many people i *didn't* rape that same day. I still go to jail for the one i did.
Firing on people helping the wounded is *not* combat no matter how many folks you *didn't* shoot before hand.
Then why doesn't apples html5 demonstration work in my html5 browser? Because I don't have a mac?
What wrong is that it doesn't matter if your browser supports all the features. It only matters that the browser identifies as safari/mac. The explanations are either incompetence or malice. I suspect both.
That's because nobody likes english teachers at school. How much more do we hate them away from school.