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China Just Made a Major Breakthrough In Nuclear Fusion Research (techienews.co.uk)
New submitter TechnoidNash writes: China announced last week a major breakthrough in the realm of nuclear fusion research. The Chinese Experimental Advanced Superconducting Tokamak (EAST), was able to heat hydrogen gas to a temperature of near 50 million degrees Celsius for an unprecedented 102 seconds. While this is nowhere near the hottest temperature that has ever been achieved in nuclear fusion research (that distinction belongs to the Large Hadron Collider which reached 4 trillion degrees Celsius), it is the longest amount of time one has been maintained.
It takes billions (not millions) of years for hydrogen atoms to fuse in the sun - that is precisely why the sun has a billions-of-years lifetime. So in building a fusion reactor, we need many orders of magnitude higher reaction rates, and to achieve them at many orders of magnitude lower densities. One way of doing this is to have much higher temperatures. The solar core temperature is about 15 million degrees and TFA has 50 million degrees for this new result, and 80 million degrees for half a second at a European reactor. This sounds unimpressive, but the reaction rates are very sensitive to temperature - proportional to about T^8 as I recall, but I didn't quickly find an online reference for this. 75 million degrees would therefore give a boost of about 5^8 which is about 400,000.
In the sun, the first reaction in the chain (proton+proton->deuterium) is the rate limiting step. In a reactor, we can provide deuterium enriched fuel and bypass this step. I don't know what the reaction rates are, but I suspect that this will be a greater benefit that the higher temperatures. You can do even better with tritium in the fuel, but your reactor becomes an intense neutron source, leading to induced radioactivity in nearby materials. Some proposed designs use these neutrons to breed more tritium from a lithium blanket around the reactor. (Once I get beyond the proton-proton chain reaction, I'm just relying on pop-science knowledge, so corrections from the more knowledgeable are welcome.)
Stars a bit more massive than the sun burn hydrogen via the CNO cycle, which has even higher temperature dependence (from memory, about T^17). I've never heard of anyone suggesting using the CNO cycle in a fusion reactor - presumably there are good reasons, but I don't know what they are. One problem is you need to wait for radioactive decays, but these have half-lives on the order of 1 to 2 minutes, and a commercial reactor would be running for much longer than that.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
https://www.lenr-forum.com/forum/index.php/Attachment/386-IEEE-brief-DeChiaro-9-2015-pdf
Dear reader, I quit reading this document as soon as I saw convicted fraudster and scam artist Andrea Rossi cited by it unironically -- as you should as well.
Hot fusion is also going nowhere until anuetronic fusion becomes practical (pro tip: it's quite a bit harder to do) because the fast neutrons eventually destroy every known material used as the plasma-facing "first" wall. That's something the ITER fanboys are not telling you (for obvious reasons).
"Politicians and diapers must be changed often, and for the same reason."
The LHC experiments concern high-energy particle physics, not fusion research. It is operating at energy scales well above plasma [unless you want to talk about "quark-gluon plasma, which is something else entirely] and at conditions which have nothing to do with nuclear fusion.
Here is why it's not the USA - scroll down to the graph for the very quick answer:
http://hardware.slashdot.org/s...
China is also dumping US 1960's-style money in to scientific research and development. Of the three major space-faring countries, China, Russia, and the USA, you'll note that only China and Russian currently have manned spaceflight programs.
China has also built the largest ground recieving dish in the world, out-doing the one in Puerto Rico by a factor of almost two.
China is rocking the 1960s American Science Research meme so hard it hurts.
Meanwhile, American politicians are arguing about whether or not climate change is real, and we slot somewhere between countries like Latvia and Lithuania in Science globally. Hong Kong, (china), Singapore, and Japan are #1,2,3 globally, if you were curious.
moox. for a new generation.
Um... the US spends more money on R&D than any other country, and more money per person than any other country except Israel and South Korea.
https://en.wikipedia.org/wiki/...
You seem to not be aware that fusion research is an open and collaborative project between all nations. We share data, equipment, tokamak run-time, and scientists. Your partisan suspicion is understandable for someone not in the know, but it's totally wrong. The fusion scientific community is well aware of what is going on at EAST (and all other major collaborative facilities), when the machine turns on, when it turns off, when there is a leak, when a diagnostic malfunctions, and when things go well.
At DIII-D (USA), we have built a "remote control room" for EAST and KSTAR so that researchers in US can operate EAST on the third shift when our colleagues in China are sleeping. Control parameters will be transferred to Hefei over the internet and diagnostics will be fed back to the monitors in almost real time.
BTW, I am a fusion research scientist based in US, but I do do some work on EAST as well as other machines.