KSTAR recent result and breakeven

[jimgraber]

TL;DR Summary

How close is Kstar to breakeven now?
Here is link to recent result: https://www.eurekalert.org/pub_releases/2020-12/nrco-kas122420.php (20 seconds at 100,000 C)
I have googled but can't find triple product or anything similar. TIA if you can.

I assume this result was from a run with ordinary hydrogen, no deuterium or tritium.
But I think the equivalent DT values are frequently calculated. Is this possible here?
TIA again

 

[Astronuc]

Eurekalert news release wasn't clear. It mentions hydrogen once, "To re-create fusion reactions that occur in the sun on Earth, hydrogen isotopes must be placed inside a fusion device like KSTAR to create a plasma state where ions and electrons are separated, and ions must be heated and maintained at high temperatures." That is not helpful. They don't explicitly mention the plasma composition.

The press release states, "it succeeded in continuous operation of plasma for 20 seconds with an ion-temperature higher than 100 million degrees, which is one of the core conditions of nuclear fusion in the 2020 KSTAR Plasma Campaign." Well, OK, yeah, but . . . .

https://www.kfe.re.kr/eng/pageView/103 - indicates H, D-D, which doesn't clarify the matter, but I would suspect that they used H₂.

https://www.kfe.re.kr/eng/post/paper_eng - page lists paper lead authors and titles, but not linked to pdfs. Disappointing! I found one paper in Journal of Nuclear Materials by typing in lead author's name and title.

OK, so we have 20 sec at 1E08 K (~8.6 keV), but don't know the ion density.

 

[jimgraber]

Thanks for the references

 

[Astronuc]

I saw a number in a paper that was 10¹⁹ m^-3 (or 10¹³ cm^-3) for ion density, but that's more or less a ball park figure. A number between 10¹³ and 10¹⁴ cm^-3 would be typical, that latter being 10 times the pressure at the same temperature. Usually, as the temperature increases, the ion and electron densities decrease, as the system is limited by pressure, which is limited by the maximum magnetic field strength.

One could possibly estimate the plasma density by equating the plasma pressure with the magnetic field pressure (force), which is proportional to B², and use the toroidal field magnetic flux density, B_θ, as an approximation.