Physics

Putting the brakes on runaway electrons brings fusion power a step closer

Putting the brakes on runaway ...
Runaway electrons can melt the solid metal walls of nuclear fusion reactors but a pair of young physicists have discovered a way to slow and control these electrons paving the way for safe nuclear fusion reactors
Runaway electrons can melt the solid metal walls of nuclear fusion reactors but a pair of young physicists have discovered a way to slow and control these electrons paving the way for safe nuclear fusion reactors
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Runaway electrons can melt the solid metal walls of nuclear fusion reactors but a pair of young physicists have discovered a way to slow and control these electrons paving the way for safe nuclear fusion reactors
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Runaway electrons can melt the solid metal walls of nuclear fusion reactors but a pair of young physicists have discovered a way to slow and control these electrons paving the way for safe nuclear fusion reactors
24-year-old Linnea Hesslow and 25-year-old Ola Embréus, risingstars in their field, are still completing their PhD studies
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24-year-old Linnea Hesslow and 25-year-old Ola Embréus, risingstars in their field, are still completing their PhD studies

A functional fusion reactor may still be a dream, but it's a dream that is slowly becoming a reality with numerous research efforts and experiments aiming to unlock the nearunlimited supply of clean energy that such a reactor would provide. The challenges scientists face in gettingnuclear fusion to work are undeniably difficult, but not insurmountable, and twoyoung physicists have recently solved one of the major problemsengineers have been grappling with for almost half a century.

Nuclear fusion is the process thatpowers our sun. Deep inside our home star, hydrogen atoms aresquashed together to form helium. This fusion process releases huge amountsof energy, but requires extremely high pressures and temperatures and has been challenging to recreate in acontrolled way here on Earth.

Last year, researchers at MIT brought us closer to a fusion future by placing plasma under what they say is the most pressure ever created in a fusion device. Now,two researchers from the Chalmers University of Technologyhave unlocked another piece of the puzzle.

One of the problems engineers havefaced as they develop modern experimental tokamak type fusion reactors is that ofrunaway electrons. These are electrons with extremely high energy that can suddenly, and unexpectedly, accelerate to incredibly highspeeds that can destroy the reactor wall without warning.

24-year-old Linnea Hesslow and 25-year-old Ola Embréus, risingstars in their field, are still completing their PhD studies
24-year-old Linnea Hesslow and 25-year-old Ola Embréus, risingstars in their field, are still completing their PhD studies

Doctoral students Linnea Hesslow andOla Embréus have devised a new technique to effectively deceleratethese runaway electrons by injecting "heavy ions", such as neon orargon, into the reactor. As the electrons collide with the highcharge in the nuclei of these ions, they slow down and become much morecontrollable.

"When we can effectively deceleraterunaway electrons, we are one step closer to a functional fusionreactor," says Linnea Hesslow.

Hesslow and Embréus have created a model that can effectively predict the electrons' energy and behavior. Using mathmatical descriptions and plasma simulations the physicists are now able to effectively control the speed of the runaway electrons without interrupting the fusion process.

The nuclear fusion challenge is not asimple or easy task to overcome, but each little development such asthis one brings us closer to the clean energy through fusion dream. The Chalmers team isincredibly optimistic that a fusion-powered future is possible.

"Many believe it will work, but it'seasier to travel to Mars than it is to achieve fusion," says Linnea Hesslow. "You could saythat we are trying to harvest stars here on earth, and that can taketime. It takes incredibly high temperatures, hotter than the centerof the sun, for us to successfully achieve fusion here on earth.That's why I hope research is given the resources needed to solve theenergy issue in time."

The discovery was recently published in the journal Physical Review Letters.

Source: Chalmers University of Technology

12 comments
Ralf Biernacki
I'm not an expert on nuclear engineering, but won't these heavy ions injected into the reactor be exposed to neutron flux and possibly transmuted into nasty isotopes? One of the advantages of fusion is that it is supposed to generate little nuclear waste. . .
ColinChambers
Your technique to decelrare excessive high-speed electrons , relating to fusion Power . Is to use H+atoms , which are greedy to gain electrons Into H2 H3 et cetera .. in which to form fusion with helium .H+ Atoms have no energy state ,but make up 63% of the universe . Jacktar
VincentWolf
Fusion is a pipe dream that will never be a reality. The future is wind, solar, geothermal.
Douglas Bennett Rogers
ITER is expected to produce 1000 MW thermal. The electron loss doesn't seem to be that big of a concern.
Winterbiker
Vincent Wolf you might want to remember that solar (PV) was a pipe dream just a few decades ago, but after a lot of research and development it is ready for commercial use. The same outcome for fusion cannot be achieved without a lot of research, besides who knows what other interesting technologies may be developed along the way.
JimFox
560 years to come up with a new idea. Fusion is science's WORST idea EVER!
PaulEckerson
Wishful thinking will aways be more successful than pessimism.
ezeflyer
A waste of resources better spent on renewables.
Christopher Nigel Phillips
As several correspondents have already noted This type of fusion power is a dead duck. The big elephant in the room is that the theory of nuclear fusion as the sun's source is most likely wrong. We do not know what the temperature is at the core, we can only measure the atmosphere ie corona = millions K, photosphere 4.5 -6kK and the view to the interior sunspot umbra is even lower. In other words logically the sun's energy source comes from outside. The most recent evidence is high speed electrons which were detected at the heliopause by Voyager probes. Since nobody has visited the North or South poles of our star we have not actually seen these electrons entering, but the circuitry has been theorised by Prof Don Scott (http://electric-cosmos.org/). The SAFIRE experiment has shown the principle in laboratory conditions (https://www.youtube.com/watch?v=-K_GBBspZjs). Tapping into this massive electrical system witnessed by solar wind and aurorae will be an engineering challenge but ultimately beneficial for mankind.
FabianLamaestra
I agree that the future is wind, solar, geothermal, and BATTERIES. Also, they guy in the picture looks like he needs some sleep.