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China's Fusion Reactor Reaches 100 Million Degrees Celsius (abc.net.au)
hackingbear shares a report from the Australian Broadcasting Corporation: The team of scientists from China's Institute of Plasma Physics announced this week that plasma in their Experimental Advanced Superconducting Tokamak (EAST) -- dubbed the 'artificial sun' -- reached a whopping 100 million degrees Celsius which is six times hotter than the core of the Sun. This temperature is the minimum required to maintain a fusion reaction that produces more power than it takes to run. The Chinese research team said they were able to achieve the record temperature through the use of various new techniques in heating and controlling the plasma, but could only maintain the state for around 10 seconds. The latest breakthrough provided experimental evidence that reaching the 100 million degrees Celsius mark is possible, according to China's Institute of Plasma Physics. "While the U.S. is putting new restrictions on nuclear technology exports to China, inventions and findings of EAST will be important contributions to the development of the International Thermonuclear Experimental Reactor (ITER)," writes Slashdot reader hackingbear. The reactor is currently being built in southern France with collaboration from 35 nations. According to the Australian Broadcasting Corporation, it is expected to be "the first device to consistently produce net energy, producing 500 megawatts of clean and sustainable power."
after which time the facility and everything within about 8 miles surrounding it ceased to exist
Some of the researchers still felt it was too cold in the office and would prefer to bump up the thermostat a little more
Also I'm pretty sure the Sun, which is considerably cooler than this, is producing more power than it absorbs.
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The protons in the core of the sun are in a temperature distribution, like a bell curve, and the average of this bell curve is way to cold for fusion. The only reason fusion happens is there are so many protons, a very few have freakishly high temperature way up the high end of the bell curve. Only those statistical outliers are fusing.
So serious question: how many oceans will that boil? It's one thing to have the moon that hot, it's another to have the head of a pin that hot. Or are the just going after temperature quantity rather than size/mass?
You're on the right track. Temperature != Heat. The plasma in the outer magnetosphere of the earth has a temperature of thousands of degrees kelvin, but it doesn't melt a spacecraft that's in it. Why? It's sparse. The average kinetic energy of particles in the plasma is high (i.e., high temperature) but the power per unit area that strikes the spacecraft is very low.
That being said, the plasma inside a Tokomak can certainly melt something. That's (part of) why there is so much effort put into magnetic confinement.
If it weren't for deadlines, nothing would be late.
That is 212 million degrees in Fahrenheit. If they did it in America it would have been much hotter.
Not just instabilities, but lack of a mechanism to capture and feed the excess energy back into the device, which was not a goal of the experiment.
When all you have is a hammer, every problem starts to look like a thumb.
While the U.S. is putting new restrictions on nuclear technology exports to China
How about instead, saying "While China is repeatedly caught attempting to steal nuclear technology from the United States"...
OK, and a linked article bashing Trump admin policies based on testimony of officials who briefed New York Times journalists under condition of anonymity? Yep, this is without question legit and unbiased.
China's Fusion Reactor Reaches 100 Million Degrees Celsius
Plasma energy sounds really large when you express it in temperature. But a more convenient gauge may be the voltage needed to accelerate the particles to velocity magnitudes correspondng to that sort of energy. This is also directly applicable to fusion systems, such as the Farnsworth-Hirsch or Bussard's Polywell, which use electric fields to accelerate the particles into the reaction volume.
Both electrons and hydrogen nuclei have a charge magnitude of 1, so dropping them across a potential difference of N volts adds N electron volts of energy to each particle. Then, if you let the plasma thermalize to a Maxwellâ"Boltzmann distribution, the electron temperature will be (by definition) the temperature of the distribution is about 2/3 that corresponding to the average electron energy.
So to go from degrees Celsius degrees (of a thermalized plasma) to electron volts: .003% drop in the bucket. (Kelvin step sizes are the same but Celsius starts at 273.15 Kelvin.)
- Subtract 273.15 - a
- Divide by 11,605 to get electron volts.
- Multiply by 2/3 to get the average energy of the electrons and ions.
That's an acceleration voltage of 6,025 volts (or 9,037 if you're going to react them before they thermalize). That's right in the ballpark for high-end vacuum tube technology - like the second anode on a CRT. (Those ran about 3000 to 6000 V in the 1940s, and about 25,000 V when modern color tubes were being replaced by flat panels.)
You can see why we all had high hopes for things like Polywell, where (if it worked as expected) a "gassy vacuum tube" that would fit in a strip-mall store's back room, with all supporting equipment (mostly mid-20th-century style electronics), and provide 100 MW of DC at cross-country power line voltages.
Of course many of the other methods for directly heating plasma heat the electrons much more than the ions. So the average energy of the plasma may be substantially lower.
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The Sun can be cooler because it has a couple of things going for it: it's optically dense and gravitationally confined. That is, the core is SO big and SO dense that radiation doesn't just leak heat out into space. So the plasma doesn't cool down immediately. Also, the plasma density is maintained by the weight of all the mass of the rest of the star.
Lab experiments, and in fact any plasma on earth, have neither of these advantages going for them.
That is why the Sun can maintain its fusion reaction and why it is so hard to create fusion on earth.
It will run at 400 - 600 seconds and will produce more energy than it consumes, that is all. There is no power plant attached nor will there ever be: https://www.iter.org/sci/Goals
And the power production is not clean as long as we use deuterium + tritium, the reactor vessel will have to be replaced around every 10 years and discarded as highly radioactive waste.
Regarding sustainability: ITER will attempt to breed tritium ... lets see how good that works. Otherwise we had to farm tritium from the sea, which is energy intensive and causes another spot in the chain to work with an radioactive element.
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Advice: don't study science. With your deep, keen insight you'll a be natural for sanitary management.
When all you have is a hammer, every problem starts to look like a thumb.
My understanding is that the energy output, per cubic meter, is about the same as the human body, 50-100 watts or whatever. Just that there are a lot of cubic meters in the core of the Sun, so it adds up. As the AC says, proton-proton fusion is slow, even at the pressures and temperatures at the core.
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They keep running into problems. I've read a few papers, and they would hit problems such as the metals used weren't strong enough to withstand the magnetic fields they were generating. That was fixed. Then the plasma rings would start to twist, buckle, warp and pinch into singularities. Stellerators fixed that problem by putting some torsion into the plasma rings. Tokamaks fixed that problem by adding extra magnetic field randomness or something to break up the standing waves. That fixed that problem. Then the neutron bombardment started poking holes in the metal structure, which weakens it over time. Maybe that has been fixed, but it keeps going round and round.
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To sustain enough steam to power the world you would need, not unsurprisingly, the entire world's current supply of oil, gas, nuclear fission, solar, wind, hydro, etc. Because... that's pretty much what we use it to do (I'm excluding all losses here, for simplicity).
One you achieve fusion, you can literally power the entire world from 867 tonnes of hydrogen per year. That's maybe a shipping container full of hydrogen. Something we can pull out of the ocean.
For reference, we would need to burn 12 billion tonnes of oil, 10.4 billion tonnes of gas or even 7000 tonnes of uranium to do the same.
Pretty much the only thing more powerful is complete utilisation of E=mc^2 - merging antimatter and matter and capturing the blast. You'd only need 3 tonnes of antimatter to power the world in that instance.
https://www.forbes.com/sites/s...
Fusion, if it can be made to work, could power the entire world from one power station. Of course, that's not what would happen - we'd just end up USING UP all that energy and every country would have half a dozen of them. We'd end up synthesising rare materials and doing all the things we can't currently do because of the sheer amount of energy they require, rather than actually just settle on current usage coming from one place.
But it literally is an order of magnitude more energy than the nuclear reactors we have now, which are orders of magnitude more energy than even coal and oil, which are orders of magnitude more energy than anything else.
And it looks like we could viably do it inside the next century or so.
With that amount of energy, you could easily obliterate the planet, or fire things into space like they were paper planes.
It isn't going "round and round" it is going forward, step by step. Each issue that is solved is one less issue. There have been at least 226 tokamaks built to date, and each one advances knowledge about some aspect of design and operation. That is how extremely complex systems are developed. There is a lot of work to be done to build and operate the first true break-even tokamak -- about 20 years and $20 billion worth.
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