100M seems insanely high, beyond what anything man made would be able to contain. Is it extremely short lived? Or over a very small area? Very interesting.
Both, really. The goal is figure out how to sustain this for an extended period of time.
Chinese Tokamak reaches over 100M degrees
21–30 of 240 posts
Re: Chinese Tokamak reaches over 100M degrees
#22Earlier quoted context omitted.
You seem to know what you're talking about - do you know what the end goal of the work in this field is? Is it working towards nuclear fusion as an energy source?
The specific EAST reactor [1] mentioned in the article is a testbed that will enable new technologies to be used on the ITER project. The ITER project [2] is currently the largest fusion power research project underway (and the largest reactor under construction). ITER's goal is to provide research that enables new technologies to be used on the DEMO project. The DEMO project's goal [3] is to provide commercially ava…
[deleted]
Re: Chinese Tokamak reaches over 100M degrees
#23Please explain what does it mean and why is it good? :) Thank you.
It’s an important milestone in the search for sustainable nuclear fusion.
Re: Chinese Tokamak reaches over 100M degrees
#24100M seems insanely high, beyond what anything man made would be able to contain. Is it extremely short lived? Or over a very small area? Very interesting.
It is incredibly high. We hold it in not by any material, but by magnetic fields. Plasma has the handy feature of being magnetic. The Tokamak[1] design used in ITER and this example uses a whole heap of magnets to hold this plasma in a doughnut-shaped area.
Re: Chinese Tokamak reaches over 100M degrees
#25Earlier quoted context omitted.
Except Wikipedia seems to put the barrier significantly higher, at 100 keV: https://en.m.wikipedia.org/wiki/Thermonuclear_fusion#Tempera...
A system of particles in thermal equilibrium will contain a small fraction whose kinetic energy exceeds the average by a factor of 10. Also, the energy available in the center-of-mass frame of two colliding particles is higher if they happen to be moving in opposite directions. That could give you another factor of up to 2. In any event, I don't think you want your fuel fusing all at once!
In addition to this there is also a quantum effect called quantum tunneling [1] which allows for a very tiny probability for particles with insufficient energy to fuse upon collision anyway.
[1] https://en.wikipedia.org/wiki/Quantum_tunnelling#Nuclear_fus...
Re: Chinese Tokamak reaches over 100M degrees
#26Stories like this scare me. With all of the precautions, even things like Fukushima failed and will poison our ocean for millennia. What happens if we have a runaway fusion process through some pathway that was unexpected? With all the talk about the LHC possibly producing mini blackholes or magnetic monopoles that could potentially cause protons to decay spontaneously, I don't have enough nuclear physics background…
https://news.ycombinator.com/item?id=18004980 Calculations have been done in general about runaway fission/fusion already. Hawking showed that mini black holes "evaporate" very rapidly, before anyone would even notice. As for some unexpected pathway, energies like this are reached in stars all the time, and they don't spontaneously explode on a regular basis. If you're talking about a basic science experiment being t…
> As for some unexpected pathway, energies like this are reached in stars all the time, and they don't spontaneously explode on a regular basis.
Well, they kind of do…
But really, the only reason why stars manage to stay in hydrostatic equilibrium is because of gravity, which we really can’t do on Earth so we settle for fancy magnetic confinement vessels.
Re: Chinese Tokamak reaches over 100M degrees
#27Okay, did some search: - When two hydrogen nuclei combine, they produce an enormous amount of energy. That process is known as nuclear fusion. - Light nuclei have to be heated to extremely high temperature, it is challenging to create a controlled, safe fusion reactor that offers more energy than it consumes. Once we have such we’d have a near-limitless source of clean energy. - Nuclear fusion does produce radioactiv…
I will add:
- While the products of the fusion reaction are short-lived, operating a fusion reactor will active materials in the reactor and create some longer-lived radioisotopes.
- Unlike a fission reactor, which is loaded with months to years worth of fuel, a fusion reactor would have fuel constantly injected. So operator action to stop injecting fuel would stop the nuclear reaction.
Re: Chinese Tokamak reaches over 100M degrees
#28Stories like this scare me. With all of the precautions, even things like Fukushima failed and will poison our ocean for millennia. What happens if we have a runaway fusion process through some pathway that was unexpected? With all the talk about the LHC possibly producing mini blackholes or magnetic monopoles that could potentially cause protons to decay spontaneously, I don't have enough nuclear physics background…
great vid: https://www.youtube.com/watch?v=KETtEHX3pwo
Re: Chinese Tokamak reaches over 100M degrees
#29Stories like this scare me. With all of the precautions, even things like Fukushima failed and will poison our ocean for millennia. What happens if we have a runaway fusion process through some pathway that was unexpected? With all the talk about the LHC possibly producing mini blackholes or magnetic monopoles that could potentially cause protons to decay spontaneously, I don't have enough nuclear physics background…
Uh, worst case it blows up pretty conventionally, lots of heat (but not really, not a lot of actual material is used), and, uh, as far as byproducts... helium? Maybe some lithium or boron o carbon or aomething if things get really wild?
Basically it's really really safe as far as byproducts. And yeah, it's a teeny sun, that instantly goes out if you stop feeding it juice, which sounds bad, but it's all the tiny stable particles, not the big slowly decaying scary ones.
Re: Chinese Tokamak reaches over 100M degrees
#30Earlier quoted context omitted.
As I understand, this represents sufficient energy to overcome the Coulomb Barrier [1] which naturally repels atoms apart. To cause fusion, you need to push particles together either hard enough or fast enough that they push through this repulsion and fuse. The repulsion is a product of the electrostatic repulsion of the positive charges of the nuclei (pushing the positive ends of two magnets together, essentially).…
Except Wikipedia seems to put the barrier significantly higher, at 100 keV: https://en.m.wikipedia.org/wiki/Thermonuclear_fusion#Tempera...
The Wiki entry also mentioned "two effects that lower the actual temperature needed", one being average kinetic energy and the other quantum tunneling "if [nuclei] have nearly enough energy." The term "nearly" isn't precisely defined though.