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Chinese Tokamak reaches over 100M degrees

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Re: Chinese Tokamak reaches over 100M degrees

#121

Post by throwawayaway12 »

mrpdaemon wrote: post #10

The main challenge in working with these high temperature plasmas is confinement. In order to achieve nuclear fusion matter needs to be heated to immense temperature, so that the kinetic energy of nuclei colliding can overcome the electrostatic force of the protons pushing each other away and "fuse" into larger nuclei (held together by the "strong force"), converting a fraction of the reaction mass into a relatively…

>The immense engineering challenge here is to heat plasma to ridiculous temperatures, and keep it confined in a very small volume at great temperature and pressure to mimic conditions that give rise to nuclear fusion in the center of stars.

This is not exactly true. Inertial confinement fusion has conditions that are similar to stars. The engineering challenge for magnetically confined fusion to keep the low density plasma confined for long time durations for fusion.

For anyone interested in further reading, look up the Lawson Criterion.

Re: Chinese Tokamak reaches over 100M degrees

#122

Post by antx »

mcv wrote: post #106
maaaats wrote: post #95

Earlier 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.

It's also wrong. Kelvin is not in degrees. It's just 100M Kelvin.

You're right, the degree was removed in 1967, because Kelvin's units are considered absolute. However, one could argue that, since it has a scale, each "step" or "unit" can be considered a "degree", like in a literal scale. In informal conversation, we should not be so pedantic. Even some modern scientific textbooks still include the degree.

Re: Chinese Tokamak reaches over 100M degrees

#123

Post by nscalf »

Since I don't see any comments mentioning this, I've heard a lot of talk about skepticism on other forums regarded Chinese scientific breakthroughs. I know on the state level, their numbers are not considered reliable (economic data for instance). Does anyone have thoughts on the reliability of this?

Re: Chinese Tokamak reaches over 100M degrees

#124

Post by throwaway857384 »

nscalf wrote: post #123

Since I don't see any comments mentioning this, I've heard a lot of talk about skepticism on other forums regarded Chinese scientific breakthroughs. I know on the state level, their numbers are not considered reliable (economic data for instance). Does anyone have thoughts on the reliability of this?

What if the discrediting of Chinese data was a type of state propaganda on America's side?

Re: Chinese Tokamak reaches over 100M degrees

#125

Post by monochromatic »

antx wrote: post #122
mcv wrote: post #106

Earlier quoted context omitted.

It's also wrong. Kelvin is not in degrees. It's just 100M Kelvin.

You're right, the degree was removed in 1967, because Kelvin's units are considered absolute. However, one could argue that, since it has a scale, each "step" or "unit" can be considered a "degree", like in a literal scale. In informal conversation, we should not be so pedantic. Even some modern scientific textbooks still include the degree.

Indeed. Nobody’s going to be confused by “degrees Kelvin.”

Re: Chinese Tokamak reaches over 100M degrees

#126

Post by monochromatic »

metaphor wrote: post #30
saagarjha wrote: post #12

Earlier quoted context omitted.

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.

There isn’t a hard limit. But as you get farther away from the amount of energy that would be “enough” without tunneling, the probability of tunneling falls off exponentially.

Re: Chinese Tokamak reaches over 100M degrees

#127

Post by 14 »

fyfy18 wrote: post #114
zaarn wrote: post #107

Earlier quoted context omitted.

Fusion is notoriously underfunded. More money means you can buy better gear, hire more workers, complete projects faster and run multiple parallel sites to complete various goals at the same time. Of course there is some point where adding more funding will not advance the speed as much anymore but I doubt were even close to that point at the moment.

Why is it so underfunded? The first country to build one will be taking a big step to reducing their dependence on other countries for energy. I can understand big oil exporters not wanting to push it too much (although it's unlikely to come into fruition for the current generation of politians), but for others isn't it a no brainer?

Same reason preventative medicine is not practiced. The upfront costs are great and the out come not certain leaving many hesitant to invest in something they may never benefit from. Especially if your country has more immediate pressing matters that you could fix right now with that money.

Re: Chinese Tokamak reaches over 100M degrees

#128

Post by b_tterc_p »

shusson wrote: post #75
mrpdaemon wrote: post #10

The main challenge in working with these high temperature plasmas is confinement. In order to achieve nuclear fusion matter needs to be heated to immense temperature, so that the kinetic energy of nuclei colliding can overcome the electrostatic force of the protons pushing each other away and "fuse" into larger nuclei (held together by the "strong force"), converting a fraction of the reaction mass into a relatively…

this is what Doctor Octavius was trying to do in Spiderman 2.

This is helpful. Thank you.

Re: Chinese Tokamak reaches over 100M degrees

#129

Post by simias »

maaaats wrote: post #95
i_am_proteus wrote: post #3

A tokamak is a kind of fusion reactor, and basically the most prevalent. "100M degrees" (Kelvin) corresponds to 10 KeV (kilo electron volts), which is an important figure to exceed for D-T fusion. D-T fusion which is the kind of fusion the ITER Tokamak (a forthcoming fusion reactor and international megaproject) intends to demonstrate. An older fusion experiment, JET (Joint European Torus) reached these levels, so th…

> "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.

Re: Chinese Tokamak reaches over 100M degrees

#130

Post by _Microft »

nickdothutton wrote: post #76

Is 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.

I think there are a number of startups building on the foundational research done for the other, larger experimental reactors that are trying to build small-scale fusion reactors, some with quick iterations on their designs (i.e. a reactor generation only takes half a year instead of 15 years). Some of them are based near the JET lab, afaik. TAE Technologies also has an own approach for example.
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