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posted by hubie on Sunday September 11 2022, @04:36PM   Printer-friendly
from the ten-years-away dept.

The director of the Korean research centre said the 2020 experiment marked an 'important turning point' in making commercial nuclear fusion reactors:

A fusion device in South Korea made a breakthrough when it maintained a temperature nearly seven times hotter than the sun for 20 seconds.

The Korea Superconducting Tokamak Advanced Research (KSTAR) reactor managed to maintain an ion temperature of more than 100m degrees Celsius "without plasma edge instabilities or impurity accumulation". The heat of centre of the sun is estimated to be around 15m degrees Celsius.

The record was hit in 2020, but the associated research paper was published this month in the journal Nature after being peer-reviewed.

The researchers noted that other fusion devices have briefly managed plasma at temperatures of 100m degrees Celsius or higher. However, none of them managed to maintain this for 10 seconds or longer.

[...] "KSTAR's success in maintaining the high-temperature plasma for 20 seconds will be an important turning point in the race for securing the technologies for the long high-performance plasma operation, a critical component of a commercial nuclear fusion reactor in the future."

The final goal of the KSTAR is to succeed in a continuous operation of 300 seconds with an ion temperature higher than 100m degrees Celsius by 2025.

I'm noticing the use more and more in these kind of articles of odd or incorrect units, here using "m" for million. What's up with that? [hubie]

Journal Reference:
Han, H., Park, S.J., Sung, C. et al. A sustained high-temperature fusion plasma regime facilitated by fast ions. Nature 609, 269–275 (2022). 10.1038/s41586-022-05008-1


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  • (Score: 0, Troll) by Anonymous Coward on Sunday September 11 2022, @04:50PM (5 children)

    by Anonymous Coward on Sunday September 11 2022, @04:50PM (#1271216)

    "100m degrees Celsius" Is that the same as 100,000,273.15 K?

    • (Score: 0) by Anonymous Coward on Sunday September 11 2022, @05:18PM

      by Anonymous Coward on Sunday September 11 2022, @05:18PM (#1271217)

      Actually, I think it converts to 273.25K.

    • (Score: 3, Informative) by istartedi on Sunday September 11 2022, @06:40PM

      by istartedi (123) on Sunday September 11 2022, @06:40PM (#1271226) Journal

      We call the units of temperature "degrees" because Fahrenheit calibrated his thermometers so that an analog dial would swing 180 *angular* degrees between freezing and boiling (212-32=180). The phrase "degrees Celsius" is accepted usage, but pure nonsense if you think about it. They attempted to introduce a SI angular measure with 100 units = pi radians, but it was never popular.

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    • (Score: 2) by legont on Sunday September 11 2022, @11:20PM (2 children)

      by legont (4179) on Sunday September 11 2022, @11:20PM (#1271252)

      They screwed the article by 10^3. The Sun's temperature is 5000 Celcuius and the core is, in theory, 15,000
      There are no millions over there.
      Now, my plasma welder can reach 25,000 Celsius - hotter than Sun's anywhere - for rather unlimited time. What the reactor did is still a mystery to me and no, I am not going to read an article like this.

      --
      "Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
      • (Score: 3, Informative) by Anonymous Coward on Monday September 12 2022, @01:03AM

        by Anonymous Coward on Monday September 12 2022, @01:03AM (#1271262)

        They specified the core of the Sun (which is good since that is where the fusion happens), which is around 15 million degrees [space.com], so I'd say their 100 million is about seven times that.

      • (Score: 2) by FatPhil on Monday September 12 2022, @01:45PM

        by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Monday September 12 2022, @01:45PM (#1271316) Homepage
        > the core is, in theory, 15,000

        Nope, no fusion would happen were that the case, and in the absence of of such energy release there would not be enough outward pressure countering the gravity (photons spend so much time pushing the plasma around they take thousands of years to emerge from the sun).
        """
        Model values at center of Sun:
        Central pressure: 2.477 x 10^11 bar
        Central temperature: 1.571 x 10^7 K
        Central density: 1.622 x 10^5 kg/m3
        """ -- https://nssdc.gsfc.nasa.gov/planetary/factsheet/sunfact.html
        --
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  • (Score: 3, Informative) by RamiK on Sunday September 11 2022, @06:20PM (5 children)

    by RamiK (1813) on Sunday September 11 2022, @06:20PM (#1271222)

    I'm noticing the use more and more in these kind of articles of odd or incorrect units, here using "m" for million. What's up with that? [hubie]

    Lower-case "m" is the acceptable form for million in the UK style guides and siliconrepublic.com is an Irish publication: https://www.theguardian.com/guardian-observer-style-guide-m [theguardian.com]

    Btw, historically the correct form is MM which happens to be the most compatible with the metric system as well. So of course, the UK opted for m while the US opted for M out of pure spite.

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    compiling...
    • (Score: 2) by hubie on Sunday September 11 2022, @07:27PM (1 child)

      by hubie (1068) on Sunday September 11 2022, @07:27PM (#1271231) Journal

      That is interesting, though not very consistent (it also says MW for megawatt and mW for milliwatt). It has mm for millimeters, but you're not supposed to use m for meters (except for sporting events), but km is acceptable. It doesn't explain pc being used for percent, though, as I've seen in other stories. The style guide says to use % for that.

      I thought that page was ridiculously long for a style guide, then realized that was only for the letter "m"! I hope they have software to check enforcement for all that stuff.

      • (Score: 3, Touché) by RamiK on Sunday September 11 2022, @08:27PM

        by RamiK (1813) on Sunday September 11 2022, @08:27PM (#1271241)

        That is interesting, though not very consistent...I hope they have software to check enforcement for all that stuff.

        Well, what you have to keep in mind is that the authors of such style guides that require human proofing happen to earn their wages as editors...

        --
        compiling...
    • (Score: 0) by Anonymous Coward on Monday September 12 2022, @04:46AM

      by Anonymous Coward on Monday September 12 2022, @04:46AM (#1271276)

      Btw, historically the correct form is MM which happens to be the most compatible with the metric system as well. So of course, the UK opted for m while the US opted for M out of pure spite.

      To make things even more confusing, in the past (before widespread adoption of SI in the industry), electrical engineers would write M for "millionth" (i.e., "micro-") and MM for "millionth of a millionth" (i.e., "pico-").

      Language is messy!

    • (Score: 2) by PiMuNu on Monday September 12 2022, @11:36AM

      by PiMuNu (3823) on Monday September 12 2022, @11:36AM (#1271303)

      The Grauniad is advising on style?

    • (Score: 2) by FatPhil on Monday September 12 2022, @01:56PM

      by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Monday September 12 2022, @01:56PM (#1271318) Homepage
      45m is a number. MW are a unit. Strictly, the number and the unit should be kept separate (not a standard I pay much attention to, to be honest), so theoretically there's never any confusion.

      I think the MM is more in economics/politics, and I think is using the reduplication-for-plural that you also see in "pp" for "pages" in references, say.
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  • (Score: 4, Touché) by progo on Sunday September 11 2022, @08:02PM (4 children)

    by progo (6356) on Sunday September 11 2022, @08:02PM (#1271235) Homepage

    > using "m" for million. What's up with that?

    I had a mental breakdown a few years ago when I read about a power plant that produces a number of megawatts per day (not joules or day or megawatts or megawatt hours per day).

    I'm still trying to get over it.

    • (Score: 3, Funny) by Gaaark on Sunday September 11 2022, @08:15PM

      by Gaaark (41) on Sunday September 11 2022, @08:15PM (#1271237) Journal

      I had a mental breakdown a few years ago

      A few years ago: is that like 12 parsecs? ;)

      --
      --- Please remind me if I haven't been civil to you: I'm channeling MDC. I have always been here. ---Gaaark 2.0 --
    • (Score: 2) by number11 on Sunday September 11 2022, @08:31PM (1 child)

      by number11 (1170) Subscriber Badge on Sunday September 11 2022, @08:31PM (#1271243)

      I attribute it to the fact that nobody (not even "Latin America") speaks Latin anymore.

      • (Score: 2) by PiMuNu on Monday September 12 2022, @11:39AM

        by PiMuNu (3823) on Monday September 12 2022, @11:39AM (#1271304)

        Ubi est Quintus? Quintus est in cubiculum. Ubi est puella? Puella est in cubiculum. Quod faciunt?

    • (Score: 3, Insightful) by FatPhil on Monday September 12 2022, @02:33PM

      by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Monday September 12 2022, @02:33PM (#1271328) Homepage
      I've always had a bit of a problem with megawatt hours per day, even though it's dimensionally correct. The Energy/power confusion is a very common one though. I think it's even more common in contexts that still use BTUs - the /h's seem to get forgotten more than the ·h's do in metricland.
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  • (Score: 2) by bradley13 on Sunday September 11 2022, @08:16PM (2 children)

    by bradley13 (3053) on Sunday September 11 2022, @08:16PM (#1271238) Homepage Journal

    Iirc, fusion mostly happens in the Sun's core, whereas the high temperatures are near the surface. So comparing this to the sun doesn't actually make much sense.

    Also, what we want to achieve in fusion doesn't even exist in nature. Fusion in the sun is actually fairly rare. The average density of energy generation is roughly equivalent to a good compost pile. We want piles of energy generation in a very small space.

    --
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    • (Score: 3, Touché) by weeds on Sunday September 11 2022, @09:42PM

      by weeds (611) on Sunday September 11 2022, @09:42PM (#1271245) Journal
      Help me out here:

      Fusion in the sun is actually fairly rare.

      A quick search on Wikipedia turned up this:

      ...converting about 3.7×10^38 protons into alpha particles (helium nuclei) every second (out of a total of ~8.9×10^56 free protons in the Sun), or about 6.2×10^11 kg/s

      So are you saying it's rare on a sun scale since there are a total of about 8.9×10^56 free protons in the Sun? I mean, on an earth scale, 6.2×10^11 kg/s is a lot.

    • (Score: 2) by FatPhil on Monday September 12 2022, @02:23PM

      by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Monday September 12 2022, @02:23PM (#1271325) Homepage
      The heat in a region of the sun isn't because of the heat generation there, it's because of the heat generation elsewhere in the sun. Heat can only escape from the sun through its surface, which is tiny compared to its volume. The whole column of the sun between the surface and the centre needs to shed its heat through that surface. Because of this, light spends way more time inside the sun than it does inside the rest of the solar system even at its loosest definition (half way to Alpha-Centauri).

      But you're right, the actual generation is surprisingly low, and that does need to be restated because it's so unexpected.

      Additional Sun Trivia: The average density of the sun is about that of dry sand, 1.4x that of water. Of course, it varies a lot from core to surface, at the core it's well over a hundred times that average (and 6 times higher than the densest macroscopic material ever made on earth).
      --
      Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
  • (Score: 2) by Username on Monday September 12 2022, @09:51AM

    by Username (4557) on Monday September 12 2022, @09:51AM (#1271289)

    Is the Sun a K-pop star?

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