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https://www.youtube.com/watch?v=KkpqA8yG9T4 https://www.youtube.com/watch?v=KkpqA8yG9T4 Here's a video lecture from the MIT Professor (Dennis Whyte) who was le

https://www.youtube.com/watch?v=KkpqA8yG9T4 https://www.youtube.com/watch?v=KkpqA8yG9T4 Here's a video lecture from the MIT Professor (Dennis Whyte) who was leading the research group that provided some of the key designs for the SPARC reactor. As the NYT article explains, that research has been spun out into a startup that raised $200M. The key breakthrough is the advancement of REBCO tape superconductors which allow you to (1) generate record breaking magnetic field strengths (2) easily disassemble the super conducting loop for fast repairs / refuels / more modular design. It's a long talk, but it's extremely fascinating. Basically everything becomes much easier once you can increase the magnetic field strength. This talk is fairly accessible to even relative laypeople who have a vague understanding of E&M physics.

woeirua 6y ago
That's a great talk, and really gives me a lot of hope for the SPARC concept that this article is about.
yboris 6y ago
Phenomenal talk! I'm still watching - so captivating.
sien 6y ago
Another excellent talk for those interested is MIT's Pathway to Fusion Energy (IAP 2017) - Zach Hartwig. https://www.youtube.com/watch?v=L0KuAx1COEk https://www.youtube.com/watch?v=L0KuAx1COEk He goes into detail about SPARC as well and why a higher magnetic field using HTS superconductors enables performance that can otherwise be obtained by greater size as ITER is trying.
maccam94 6y ago
Timeline (in case you want to skip over some parts): 00:01:00 - introducing Dennis Whyte, MIT department head for nuclear science 00:04:24 - presentation starts 00:06:00 - identifies breakthrough with REBCO magnets 00:07:25 - explains deuterium-tritium fusion 00:12:30 - basic metrics for reactor performance 00:17:15 - energy output of other previous fusion experiments 00:19:00 - examines ITER and the problems of its approach 00:22:00 - problems solved by high energy magnetic fields 00:28:15 - full scale reactor concept, teardown of REBCO magnets 00:37:00 - design limits and margins 00:39:00 - fixes plasma instabilities found in weaker magnetic chambers 00:40:00 - maintainability, lifespan, component replacement 00:45:00 - solution to neutron damage and energy capture 00:50:30 - cost and profitability 00:54:00 - full graph of field strength vs reactor scale (and thus funding requirements) 01:01:50 - Q&A 01:30:00 - question about the biggest risks Also a more recent video, with more numbers and even more confidence than the first: https://www.youtube.com/watch?v=rY6U4wB-oYM https://www.youtube.com/watch?v=rY6U4wB-oYM
- Robotbeat 6y ago
  I think they're using Yttrium (i.e. YBCO), right? It's hard to find that info.
  - hyperion2010 6y ago
    Buried in the wiki page for YBCO is a note that REBCO is a synonym of sorts. The superconducting tapes that are discussed in the talk thus would seem to be YBCO.
    - Robotbeat 6y ago
      Yes. Re stands for "rare earth," and yttrium is probably the most common one used for ReBCO, but lanthanum is also used.
  - dbetteridge 6y ago
    https://nationalmaglab.org/magnet-development/magnet-science-technology/publications-mst/highlights-mst/high-temperature-superconducting-rebco-tapes https://nationalmaglab.org/magnet-development/magnet-science... Looks like they 'only' need to be at 4.2Kelvin as well to operate, which is a definite improvement
    - MertsA 6y ago
      They don't need to be that cold to start superconducting, 4.2K is just the temperature you could expect with liquid helium cooling. It would actually be superconducting with liquid nitrogen but the reason why you would still want to go colder is because superconductors have a maximum magnetic flux that they can sustain while still being superconducting. The current travelling through a superconductor itself also contributes to the magnetic flux so even though it's superconducting there's still a limit as to how much current you can pass through a conductor and how high of a magnetic field you can create. This limit is dependent on temperature though, so you definitely want to use liquid helium so you can create a much stronger magnetic field.

woeirua 6y ago

That's a great talk, and really gives me a lot of hope for the SPARC concept that this article is about.

yboris 6y ago

Phenomenal talk! I'm still watching - so captivating.

sien 6y ago

Another excellent talk for those interested is MIT's Pathway to Fusion Energy (IAP 2017) - Zach Hartwig. https://www.youtube.com/watch?v=L0KuAx1COEk https://www.youtube.com/watch?v=L0KuAx1COEk He goes into detail about SPARC as well and why a higher magnetic field using HTS superconductors enables performance that can otherwise be obtained by greater size as ITER is trying.

maccam94 6y ago

Timeline (in case you want to skip over some parts): 00:01:00 - introducing Dennis Whyte, MIT department head for nuclear science 00:04:24 - presentation starts 00:06:00 - identifies breakthrough with REBCO magnets 00:07:25 - explains deuterium-tritium fusion 00:12:30 - basic metrics for reactor performance 00:17:15 - energy output of other previous fusion experiments 00:19:00 - examines ITER and the problems of its approach 00:22:00 - problems solved by high energy magnetic fields 00:28:15 - full scale reactor concept, teardown of REBCO magnets 00:37:00 - design limits and margins 00:39:00 - fixes plasma instabilities found in weaker magnetic chambers 00:40:00 - maintainability, lifespan, component replacement 00:45:00 - solution to neutron damage and energy capture 00:50:30 - cost and profitability 00:54:00 - full graph of field strength vs reactor scale (and thus funding requirements) 01:01:50 - Q&A 01:30:00 - question about the biggest risks Also a more recent video, with more numbers and even more confidence than the first: https://www.youtube.com/watch?v=rY6U4wB-oYM https://www.youtube.com/watch?v=rY6U4wB-oYM

Robotbeat 6y ago
I think they're using Yttrium (i.e. YBCO), right? It's hard to find that info.
- hyperion2010 6y ago
  Buried in the wiki page for YBCO is a note that REBCO is a synonym of sorts. The superconducting tapes that are discussed in the talk thus would seem to be YBCO.
  - Robotbeat 6y ago
    Yes. Re stands for "rare earth," and yttrium is probably the most common one used for ReBCO, but lanthanum is also used.
- dbetteridge 6y ago
  https://nationalmaglab.org/magnet-development/magnet-science-technology/publications-mst/highlights-mst/high-temperature-superconducting-rebco-tapes https://nationalmaglab.org/magnet-development/magnet-science... Looks like they 'only' need to be at 4.2Kelvin as well to operate, which is a definite improvement
  - MertsA 6y ago
    They don't need to be that cold to start superconducting, 4.2K is just the temperature you could expect with liquid helium cooling. It would actually be superconducting with liquid nitrogen but the reason why you would still want to go colder is because superconductors have a maximum magnetic flux that they can sustain while still being superconducting. The current travelling through a superconductor itself also contributes to the magnetic flux so even though it's superconducting there's still a limit as to how much current you can pass through a conductor and how high of a magnetic field you can create. This limit is dependent on temperature though, so you definitely want to use liquid helium so you can create a much stronger magnetic field.