How are these results more (or less) significant than the stellerator (Germany) achieved earlier this year?
I thought the stellerator had already achieved 100M Kelvin?
Chinese Tokamak reaches over 100M degrees
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Re: Chinese Tokamak reaches over 100M degrees
#152Earlier quoted context omitted.
If global warming will be more significant then is predicted now I believe they will suddenly invest 100x more into this technology. This and nuclear plants are only reasonable way how to have available energy for some 'CO2 removal' projects...
Is money more limiting than time though? Nine woman and a child analogy comes to mind.
Nine women can't have one child faster, but on average they can have about nine times as many children in nine months as one woman. It really depends what your goal is and the bottleneck in reaching that goal whether or not that analogy holds.
Re: Chinese Tokamak reaches over 100M degrees
#153If you added one gram of 100M degree material in a 5 sq meter room at 15 degrees C, how hot would the room get?
Well.. assuming the room is about 3 meters high, that's a room volume of 15 cubic meters. Assuming it's filled with air, and air weighs about 1,29 kg per cubic meter, that's 19,35 kg or 19350 grams of air. 15 degrees C is 288 Kelvin, so that's 19350*288 = 5.572.800 gram-kelvins of energy in the room initially. Now we add 100.000.000 gram-kelvins (the one gram of hot stuff) to it, and assuming this energy distributes over the air contents, our air now has a heat energy of 105.572.800 gram-kelvins. Dividing it back the same way (over the 19350 grams of air) gives us 105572800/19350 = 5456 gram-kelvins per gram of air, so a temperature of 5456 kelvins or 5183 degrees C. Still pretty hot.
Re: Chinese Tokamak reaches over 100M degrees
#154If you added one gram of 100M degree material in a 5 sq meter room at 15 degrees C, how hot would the room get?
I think a gram is significantly more material than fusion reactors need to use.
Re: Chinese Tokamak reaches over 100M degrees
#155Earlier quoted context omitted.
Well, there is almost certainly somebody that read the number and thought about Fahrenheit.
Do scientists use farenheit? Genuine question
Some. Not the physicists or astronomers, but some Americans who work with data from non-scientists regularly stay with the units in the data. Some engineers, those who are dealing with older equipment, stick with the units used when the equipment was built. US pilots and aerospace generally still talk in knots and feet of altitude.
Re: Chinese Tokamak reaches over 100M degrees
#156Earlier quoted context omitted.
> "100M degrees" (Kelvin) Off topic, but this distinction made me laugh. Like the difference between Kelvin and Celsius would throw everything off.
I remember seeing an infografic a while ago where some very high temperature of like 10 million Kelvins was displayed like "9999728 degrees". I thought it was mildly amusing.
That was probably this: https://www.reddit.com/r/space/comments/2uzgpa/from_absolute...
Re: Chinese Tokamak reaches over 100M degrees
#157Is it just me, or have we converged on 1 reactor design (the tokamak) relatively early on in the process? I appreciate that funds need to be concentrated in order to have an impact, but we have built dozens of this design since the 1950s, yet here we are.
Wendelstein 7-X in Germany is a stellarator-type reactor: https://en.wikipedia.org/wiki/Wendelstein_7-X
And YC is invested in Helion Energy using pulsed inertial fusion. Though the tokamak seems closest to being functional. The MIT ARC design is theoretically supposed to be able to work, at least on paper:
>The ARC design aims to achieve an engineering gain of three (to produce three times the electricity required to operate the machine) while being about half the diameter of the ITER reactor and cheaper to construct. (Wikipedia)
It's not been built because of the $5bn or so cost, though given global warming / saving the planet type issues I'd be happy enough as a tax payer to have governments fund one and maybe knock 1% off the defence budget to counter that. It'd probably do more for world peace than churning out some more f35s.
Re: Chinese Tokamak reaches over 100M degrees
#158Stories 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…
Low quality news aside, the LHC never had a risk of producing micro-blackholes that could cause any damage. Very tiny blackholes evaporate instantly, before they have time to do anything. The LHC would detected this, which has not happened.
Re: Chinese Tokamak reaches over 100M degrees
#159Earlier quoted context omitted.
Didn't old-school CRT televisions "heat" electrons to more than 10KeV?
I don't know about CRT's but 10KeV is not particularly energetic. A CT unit may operate in the ~100-200kV range (so max energy of 200keV) while radiation therapy units operate in 6MV-18MV range (so electron accelerated up to 18x10^6 eV). I don't know much about fusion, but my guess is the 10keV is impressive because it is a self-sustaining fusion reaction rather than being impressive because of the absolute energy of…
>> edit: someone down the page mentioned that containment is the issue.
Right, and that was my understanding. It's easy to accelerate a particle or a stream of them to high energy. It's another thing entirely to contain a gas/plasma at those energies. The distinction becomes more obvious when they flip back and forth between impressive sounding temperatures and simple KeV measures.