Fusion power has the potential to provide clean and safe energy that is free from carbon dioxide emissions. However, imitating the solar energy process is a difficult task to achieve. Two young plasma physicists at Chalmers University of Technology have developed a technology model that could lead to better methods for decelerating runaway electrons that could destroy a future reactor without warning.
It takes high pressure and temperatures of about 150 million degrees to get atoms to fuse. Additionally, runaway electrons wreak havoc in the fusion reactors that are currently being developed. In tokamak reactors, unwanted electric fields could jeopardise the entire process. Electrons with extremely high energy can suddenly accelerate to speeds so high that they destroy the reactor wall.
It is these runaway electrons that doctoral students Linnea Hesslow and Ola Embréus have successfully identified and decelerated. Together with their advisor, Professor Tünde Fülöp at the Chalmers Department of Physics, they have effectively decelerated runaway electrons by injecting so-called heavy ions of neon or argon in the form of gas or pellets.
When the electrons collide with the high charge in the nuclei of the ions, they encounter resistance and lose speed. The many collisions make the speed controllable and enable the fusion process to continue. Using mathematical descriptions and plasma simulations, it is possible to predict the electrons' energy—and how it changes under different conditions.
"When we can effectively decelerate runaway electrons, we are one step closer to a functional fusion reactor. Considering there are so few options for solving the world's growing energy needs in a sustainable way, fusion energy is incredibly exciting, since it derives its fuel from ordinary seawater," says Linnea Hesslow.
She and her colleagues recently had their article published in the reputed journal Physical Review Letters. "The interest in this work is enormous. The knowledge is needed for future large-scale experiments and provides hope for solving difficult problems. We expect the work to make a big impact going forward," says Professor Tünde Fülöp.
Despite the great progress made in fusion energy research over the past fifty years, there is still no commercial fusion power plant in existence. Right now, all eyes are on the international research collaboration related to the ITER reactor in southern France.
"Many believe it will work, but it's easier to travel to Mars than it is to achieve fusion. You could say that we are trying to harvest stars here on Earth, and that can take time. It takes incredibly high temperatures, hotter than the center of the sun, for us to successfully achieve fusion here on earth. That's why I hope research is given the resources needed to solve the energy issue in time," says Linnea Hesslow.
Facts: Fusion energy and runaway electrons
Fusion energy occurs when light atomic nuclei are combined using high pressure and extremely high temperatures of about 150 million degrees Celsius. The energy is created the same way as in the sun. Fusion power is a much safer alternative to nuclear power, which is based on the splitting (fission) of heavy atoms. If something goes wrong in a fusion reactor, the entire process stops and it grows cold. Unlike with a nuclear accident, there is no risk of the surrounding environment being affected. The fuel in a fusion reactor weighs no more than a stamp, and the raw materials come from ordinary seawater.
Explore further:
Small-scale nuclear fusion may be a new energy source
More information:
L. Hesslow et al, Effect of Partially Screened Nuclei on Fast-Electron Dynamics, Physical Review Letters (2017). DOI: 10.1103/PhysRevLett.118.255001
Eikka
Yes and no. Fusion reactors have produced more power than needed to sustain them, but then the instabilities in the plasma shut it down before it manages to make more energy than it took to prime the system.
It's like a car engine that starts and runs, but sputters out before it manages to recharge the starter battery.
Old_C_Code
The hottest the Sun (it's corona) gets is roughly 2 million degrees spawning fusion. Seems like they're missing something.
Whydening Gyre
antialias_physorg
Fusion happens in the core of the sun (at roughly 15 million degrees) - not in the corona.
What they mean is that they need 150 million degrees on Earth (because the fusion reactors we have can't replicate the immense pressure)
Basically you have to fulfill the Lawson criterium (which depends on temperature AND pressure)
katesisco
In other words, we could be clams learning to live exposed to the sun. Everyone now understands the pyramids were efforts to preserve a electrically alive and magnetically charged environment in a minimum way to preserve life. Again, such effort! And so little result.
antialias_physorg
Jun 21, 2017rderkis
You are without a doubt delusional!
I don't believe that, so that makes your statement a lie from the get go.
And I could not find anyone personally that believes that. I have talked to my neighbors and family and none of them believe that.
Fusion is just around the corner. And it will be fun pointing it out to all of you that renounced fusion based on vapor ideas.
rderkis
The only thing good about your belief is that it sounds like you don't believe it just to make yourself sound smart. Many on here try to be rebels because they think that makes them appear/sound smart. I find that particularly true of the atheists on here but there are many others.
Zzzzzzzz
Merrit
rderkis
I think they are trying that with the fusion reactors that use pistons.
Myself I believe they will achieve it with the principles the ITER is using. The trouble with the ITER is it is trying to use old technology. An example is the superconductor magnets can be built almost twice as strong now which means a reduction in size of 90% and a exponential reduction in cost.
Which translates to much faster turn around time in perfecting it.
This is what MIT's SPARC and ARC will use. check out their youtube videos.
antialias_physorg
They are doing this already. There's several ways to get the pressure/temperature criteria fulfilled. In tokamaks and stelllarators it's done via magnetic confinement (shaped by huge amounts of current in supecooled wires or the plasma directly ) . In laser fusion systems it's by shooting lasers at fuel pellets from all sides which sets up a shockwave that increases the pressure in the center.
Both have their advantages and drawbacks. Using magnetic confinement pressure is not nearly as strong as with a laser induced shockwave. however stellarator confinement designs can be used for continuous power generation (which is sort of the main goal). Tokamaks also use magnetic fields but they aren't strong enough for continuous operation because they use the plasma to conduct the electric power instead of superconducting coils- which limits the current)
Old_C_Code
Just like requiring a big bang, that makes no sense at all. "The beginning" an impossible question, foolish to make so significant.
And fusion does happen in the corona (too if you insist). I'm aware of the theory, too bad you're missing 2/3 of the neutrinos required in a fusion reaction that size.
Theses are the exceptions which make astronomers look stupid. Sorry just my opinion.
TheGhostofOtto1923
http://generalfusion.com/
rderkis
Why do they look stupid, unless perhaps they are calling someone else stupid? :-)
Astronomers, theoretical physicist even some branches of math are based on theory.
As long as they don't try to present their theories as facts they don't seem stupid. Are you telling us you know the facts?
rderkis
You know a couple of things that surprised me when I heard them. Both came from a different group of scientists that were at prestigious conferences and since no body took exception or were surprised, I imagine they are true.
1st. The large hadron collider and the other colliders smash particles together at the energy level of two mosquitoes colliding head on in flight. :-) Amazing!
2nd one at a conference on fusion. The energy density of the sun is about the same as your compost garden at home. It's just so large with so much mass, that ends up being a lot of energy.
Merrit
Fusion also has the problem of turning hydrogen into heavier elements. If fusion does become mainstream, then we could likely upset our elemental balance over time. Could be even worse then global warming.
rderkis
Why am I so confident? Because we will soon be enhancing the WHOLE human races intelligence level by steps.
First maybe only 10%, but 10% is a lot spread over the whole race. And that will give us the boost to know how to take it to 20%. .. AND ON AND ON..
Quote
Key words here are "over time."
We will be well beyond that before "over time" happens.
dirk_bruere
antialias_physorg
I dunno. Windfarms don't work particularly well in space. Neither do solar panels once you go further out in the solar system.
We need fusion in any case. If we can also use it on Earth as an additional source - all the better (e.g. for ocean-floor settlements where wind and solar aren't available).
What is this 'elemental balance' supposed to be?
The heavy element that fusion generates is helium - which isn't a problem. Also the amount of fuel is very small. A 1.5 GW reactor would use about 1kg of fuel per day (60/40 mix of tritium and deuterium)
Old_C_Code
nikola_milovic_378
Jun 22, 2017nikola_milovic_378
Jun 22, 2017rderkis
Of course they don't know what they are doing, it is all theoretical and has never been done before.
Old_C_Code
Jun 22, 2017antialias_physorg
China and India are trying out a few reactors, but that's about it. They aren't economical (and they aren't as safe as they're cracked up to be)
Dingbone
Jun 23, 2017rderkis
Cold fusion :-)
Personally I think cold fusion is probably possible. It's just that they have no idea how to do it. I am hoping with the emergence of quantum computers and their ability to do truly advanced simulations, they will show us how. :-)
But for now that is not anything but hope. :-)
Dingbone
Jun 23, 2017rderkis
When I say "how to do it" I am talking about not just repeatability but output to. We could probably harness fireflies for energy but that does not mean it's practical. I have heard it said many times "if only we had the fusion of the sun". But the sun's energy density is no greater than your backyard compost pile. In other words even if you can produce cold fusion it would not mean there is enough energy density to do anything with it.
Dingbone
Jun 24, 2017Lex Talonis
Idiots.
rderkis
So your telling us harnessing fireflies for energy is practical? It is just a modest beginning right now?
Look, if what you're saying about cold fusion is true within 6 months it will be powering our homes not hidden somewhere with skeptics. Unless of course your a conspiracy theorist, in which case your not a rational human being and there is no hope for you.
Dingbone
Jun 25, 2017Dingbone
Jun 25, 2017rderkis
I am sure your joking or if really believe that in which case I feel sorry for you.
Please tell me your joking or you will be the first person I ever ignored/muted because they are just plane crazy and living in their own reality.
Dingbone
Jun 25, 2017Dingbone
Jun 25, 2017Dingbone
Jun 25, 2017Dingbone
Jun 25, 2017Dingbone
Jun 25, 2017rderkis
I think I did not make myself clear. I believe cold fusion is possible. I just don't believe much in conspiracies.
And I don't believe cold fusion has ever been done at least not in such a way that it could produce a useable amount of energy. I think they are going at it all wrong but I have no answers.
I do believe once the true power of quantum computers is achieved it will show us the way to usable cold fusion with simulations.
There are probably many many ways to produce fusion and the quantum computer will show us the best way.
If you know how to produce cold fusion do it and became wealthy beyond your wildest dreams. If not I put it in the same filing cabinet as gas engines that run on water.
Dingbone
Jun 25, 2017rderkis
I don't think they did ignore it, they checked the research and experiments out and dismissed it as not feasible in the manner they are currently trying. I think it's probably possible but it's just we have no idea how.
Of course the idea of cold fusion has even more advantages than you and I can imagine, but that does not make it feasible.
We have 2 maybe 3 technologies that we are on the edge of, that are going to change everything and bring about a utopia on earth. None of the 3 are really science fiction since we are doing them but we are still in the first generation.
Dingbone
Jun 25, 2017rderkis
Why don't you and get rich and famous? :-)
Just think you can heat and cool your home for free! :-)
Myself I will believe the people that are much smarter than me, that looked at it then moved on.
rderkis
I am 70 and get things mixed up but that was the just of it.
Dingbone
Jun 26, 2017Dingbone
Jun 26, 2017Dingbone
Jun 26, 2017EnricM
Not a problem at all!!! I just hope they produce enough for practical uses such as Zeppelins!!!
antialias_physorg
(Read: No. It's not going to be a relevant source of helium)
Just for giggles:
A back-of-the-envelope calc* for the HAV-304
https://en.wikipe...ander_10
gives me about 7000kg worth of Helium to fill 'er up.
*for some reason the makers of airships don't post any numbers on how much helium they need
Also note that the helium is produced as bare helium nuclei. (Read: alpha radiation). It's not up for collection from the chamber.
rderkis
Dingbone
Jun 26, 2017SEM-fusor
In my computer simulation both electrons and deuterium ions stay confined in a (small) vacuum chamber up to speeds larger than needed for fusion, with a magnetic field of about 1,5 tesla and a couple of charged rings and spheres of +/- 200 kV.
It seems to be a new idea (and no patent, free to use for everybody) and perhaps an "easy" way to achieve fusion ?
See sem-fusor.com
Please copy this information here into your computer (I just saw the movie "Chain Reaction" :).
Or check my calculations and tell me if there is something not correct, or it isn´t a new idea.
Thank you.
rderkis
proponent? I think he was co-founder.
Please tell us which well recognized, major theories you have founded, even if they proved not to be true. Was Einstein ever wrong? Yet if he made a statement that I decided was wrong, would you side with me, just because I said so?
I don't pretend to understand fusion but if its a atomic reaction and energy is given off, doesn't that energy have to be electron, proton, or neutron? And a close proximity without shielding which one can not hurt you?
Dingbone
Jun 26, 2017Dingbone
Jun 26, 2017rderkis
Does that list include either you or I as recognized work?
Whydening Gyre
Don't you really mean free of "free" neutrons...?
It appears "cold fusion" just includes resident neutrons AND protons in the fusion process...
This would really mean - rearrangement(relaxing) of forces binding (strong weak, EM) the nucleon particles together to allow for additional particles...
rderkis
Sure doesn't sound like energy we could use. To be honest it does not sound like energy to me at all but it does sound like the con they use to fuel cars with water.
Just out of curiosity, please tell me you didn't buy into that hocus pocus.
Dingbone
Jun 27, 2017Dingbone
Jun 27, 2017cortezz
Nowadays, we can nanostructure surfaces and make them have massive amounts of more surface area but still no one have reported anything like that.
You seemed like a smart guy but your credibility just vanished when I actually looked some of these things up.
Dingbone
Jun 27, 2017Dingbone
Jun 27, 2017cortezz
I'm no cold fusion skeptic, just a general skeptic. And I do know stuff about surface chemistry even though I'm no expert of fusion and physics. I randomly checked few papers which seemed good from the link and I'm not fully convinced.
First of all, why all the papers are from the 20th century? Hasn't anybody done reseach in almost twenty years on the area? Also, most of the "publications" are from conferences or from low impact factor journals (or in wrong languages). Yet, there seems to be findings of excess heat and helium. I wonder why no one has build actual generators to use this power if it is so simple. Just throw electricity into a rod immersed in heavy water.
Dingbone
Jun 27, 2017Whydening Gyre
Since Fleischman-Pons(?), cold fusion has been considered a career suicide research event...
That, in and of itself, can have a pretty chilling effect...
antialias_physorg
There's still people looking into it, Though you won't find it under the name 'cold fusion'. Currently the term is LENR (low energy nuclear reactions).
Plenty of people have claimed to have built one. Turned out to be a scam in each case (no surprise, there).
Physics is just that way. You can't cheat the Coulomb barrier that easily - no matter how hard you wished you could.
TheGhostofOtto1923
https://www.youtu...ODin2Uy0
Dingbone
Jun 27, 2017cortezz
That's more convincing. Someone should do a show like mythbusters but with very hard science content. All kinds of theories and devices could be tested with appropriate experts on the field. I think it would get views.
rderkis
Those people swear they are being totally logical.
This is the thinking of the people that are so dead set against President Trump. People that would see our nation destroyed before they admitted they were wrong about a single issue.
antialias_physorg
I didn't call the LENR research a scam. Researching this is perfectly fine.
I called those who have claimed to have already built a working generator a scam (because they somehow either never work when someone shows up or they are never presented to be tested...and the ones that have been sold - e.g. to the DOE - turned out not to work)
Dingbone
Jun 28, 2017cortezz
Don't these people know how to patent?
antialias_physorg
And yet YOU know all about it...weird, huh?
Yet another world spanning super secret conspiracy that some guy with an internet connection winkled out. What are the odds? You are certainly the Sherlock Holmes among Sherlock Holmes'.
Dingbone
Jun 28, 2017antialias_physorg
You assert this stuff exists. But in the next post you assert that you don't know this stuff exists.
Ya know: You're pretty crazy.
Dingbone
Jun 28, 2017rderkis
What a terrible thing to call someone!
Is that anything like a air hater? :-)
Whydening Gyre
Waiting for the patent to run out...
Dingbone
Jun 30, 2017TheGhostofOtto1923
This is not a proper dialectic aa. If you challenge someone, you have the responsibility of acknowledging it when they prove you wrong.
I know it's not fun but it's the decent thing to do.