Z-Pinch Renaissance

[Giorgio]

Plus, break even with such a tiny device would be very different from JT-60.

Not only more tiny, but also orders of magnitude less complex than JT-60.
If they really get to break even it will be indeed a game changer in the industry.

[mvanwink5]

I have ignored most alternative fusion devices (my mistake), so I was caught by surprise that these guys have made significant progress. The scaling of 10exp11 with respect to current is a shocker, and they tested at 600kA already and need only increase amperage to 1.3 mega amps for Q=20.

The interview was insightful also as it showed the ignorance of the fission people, likely not all, but this interviewee was an eye opener. ITER is as far as this interviewee has been previously exposed and he had trouble understanding how the Z-Pinch worked, he kept thinking the magnetic field was externally applied and needed heavy structure. Perhaps there has been no previous interest in some of them in fusion because of the issues with ITER and lack of publicity of alternatives, majority of the fission guys?

Boy are they going to be shocked.

[mvanwink5]

The Z-Pinch device in development by this company will be a competitor with GF, but not Helion, IMO, as they intend to utilize the traditional steam turbine plant for conversion of power to electricity. On the other hand, Helion uses direct conversion. They are both exciting approaches.

[Skipjack]

The Z-Pinch device in development by this company will be a competitor with GF, but not Helion, IMO, as they intend to utilize the traditional steam turbine plant for conversion of power to electricity. On the other hand, Helion uses direct conversion. They are both exciting approaches.

I agree with that. Both approaches are very exciting to me as well. Mind you, David Kirtley of Helion also speaks very highly and with a lot of respect of Uri and ZAP (though naturally he favors his own approach over theirs ).

And both companies have been going through rapid development in recent years. ZAP especially has been making huge strides. From what I understand they were able to get FuZE up to 500 kA (which is much higher than the 300 kA that Uri originally expected and that FuZE was designed for) a huge jump from the 50 kA or so that they achieved with ZAP-HD.
From the looks of it, their scaling laws are still holding up and they only need another 100 to 150 kA to get to notional break even. They will need a new device for that though (FuZE-Q).

Both approaches have their pros and cons. As you mention, ZAP will need a traditional steam power plant and will have to deal with high energy neutrons.
From what I understand the capacitors and switches are also taxed a bit more with ZAP's design.
Another big challenge for them to overcome will be electrode erosion during long term operation at high currents. For stationary terrestrial applications, they plan to use a liquid outer electrode (sort of a waterfall, pretty cool design), which helps a lot. The inner one will be a bit more challenging.
There is however significant research already being conducted in this field. IIRC, DPFs have been operating at higher currents (>1 MA) for years.

On the upside, ZAP's "reactor" core will be much simpler and much more compact. I mean, this thing would be small enough to fit into anything from trains to larger air planes.
So they gain some on one side (complexity and size of the core) and lose some on the other (supporting steam plant and pulsed power system).
The market is big and diverse enough to support a several fusion generator designs. So I don't think that any of the front runners really need to worry about competition, at least not for a long time. In any case, between Helion's Polaris and ZAP's FuZE-Q 2023 will be a huge year for fusion.

[mvanwink5]

I believe neutral beam injection along the axis of current flow would provide the shear needed to disrupt the kink and sausage plasma instabilities, and since the plasma is less than a millimeter in diameter during compression would nearly be the only way to do it. Perhaps that is why they recruited this physicist for their team early on because of his prior project with the oil exploration company. Their secret sauce is not geometry, LOL. But it is simple.

[Skipjack]

I believe neutral beam injection along the axis of current flow would provide the shear needed to disrupt the kink and sausage plasma instabilities, and since the plasma is less than a millimeter in diameter during compression would nearly be the only way to do it. Perhaps that is why they recruited this physicist for their team early on because of his prior project with the oil exploration company. Their secret sauce is not geometry, LOL. But it is simple.

They don't even need neutral beam injection. It is the speed of the plasma near the outer electrode vs the inner electrode that induces the sheared flow.

[mvanwink5]

https://arpa-e.energy.gov/sites/default ... d_2016.pdf

Went back and found this at beginning of thread, it clears up my misunderstanding of the device. The device is a combination of plasma accelerator and a Z pinch. The device is elegant and enables a timed current injection to create the axial shear flow. Really a brilliant device. It really begs the question of why it has taken so long to scale up, it is not a complex device and the components are not that expensive in the scheme of fusion devices. LOL. Maybe if I read more I will better understand why...

[crowberry]

And both companies have been going through rapid development in recent years. ZAP especially has been making huge strides. From what I understand they were able to get FuZE up to 500 kA (which is much higher than the 300 kA that Uri originally expected and that FuZE was designed for) a huge jump from the 50 kA or so that they achieved with ZAP-HD.
From the looks of it, their scaling laws are still holding up and they only need another 100 to 150 kA to get to notional break even. They will need a new device for that though (FuZE-Q).

ZAP Energy announced a while ago that they have a "new facility" which is operational and that they do z-pinches and fusion with it. I wonder what "new facility" actually means? Is it a new lab with the equipment moved from the old lab or is it a new lab with a new device? If they plan to achieve break even in 2023, then I guess that they should have their FuZE-Q device operational now or at least in the near future.

[mvanwink5]

In the interview linked above 'Scientific breakeven', Q>1, is expected as early as the end of this year, and that requires 600kA. So they must have the new upgraded device in service.

The building that they just got 'the keys' for is to be used for development of systems needed for commercial, which is Q>20.

[Skipjack]

In the interview linked above 'Scientific breakeven', Q>1, is expected as early as the end of this year, and that requires 600kA. So they must have the new upgraded device in service.

The building that they just got 'the keys' for is to be used for development of systems needed for commercial, which is Q>20.

They moved out of the UW lab into a lab that belongs to ZAP. According to their abstract for this year's APS meeting, they are planning for Q>1 with FuZE-Q in early 2023. They might get there sooner if things go extremely well.
As for why it has been taking so long: Funding. They were essentially working with power supplies and other equipment that was salvaged from another experiment, IIRC. They only got the funding for FuZE-Q recently through private investments.
FuZE was designed for 300kA. When I talked to Uri in early 2018, he did not believe that FuZE could handle more structurally. So it is actually pretty cool that they managed to drive it up to 500 kA.
Uri is generally extremely cautious and careful not to over- promise anything. That is why it is very possible that they might get to Q>1 sooner than 2023. Their original estimate (on their website for a few weeks before they took it down) talked about 2022, IIRC.
I believe that their move to the new lab was delayed by a few months due to Covid. So that is another delay they were facing. Not sure how that affected their Q>1 plans, but it seems like there is a not that big of a delay there.

[mvanwink5]

SJ,
In the above youtube video the Ben Levitt said end of this year for the new machine to be on line they will use to demonstrate Scientific breakeven, Q>1. The existing machine has already been moved and in the process of recommissioning as of this video, July 2021, soon is the descriptive word. So, yes you are right, not end of the year target for Q>1, just the new machine that is targeted to reach this milestone should be up and running. Personnel will be doubled in the next 12 to 18 months. Further Ben says in the next 18 months for proving Q>1, so that would be beginning of 2023 (who knows what it will really be until it is done).
at the 20 minute point Ben talks about this
https://www.youtube.com/watch?v=rsTKcb5KSig

Sorry for the multiple edits, Ben was talking fast trying to complete a sentence, so it was all running together.

[Skipjack]

Yes, I saw that one (I even think I posted it here, didn't I). I think they have a chance to achieve Q>1 before the 2023 deadline IF everything goes really well. 2023 is still pretty soon, though. I think that the 2023 date in the APS abstract is a pretty solid base for us to base our expectations on. If they get there sooner, that would be great, but things usually take longer. That said, they exceeded their own expectations with FuZE. So they might surprise themselves and us...

[mvanwink5]

Yes, indeed, you were the one who posted the link. I got so excited when I watched it and yet pissed off at the guy doing the interview. He kept interrupting because he did not understand anything. I myself was struggling to see how the current going from electrode to the wall would create the coaxial current, so that was bothering me too but the jerk would not let Ben explain it. It wasn't until I found the paper at the beginning of this whole thread that showed that the current to the wall was pushed to the end of the long tube creating a coaxial current that I could understand it. The electrode itself starts the coaxial current and the proper magnetic field to do this.

Anyway, I think your characterization of extreme conservatism of Uri in setting public target dates explains a lot. I mean they are already at 500 KA, they are hiring like mad, they are gearing up to do engineering work in parallel to their lab machine work, it all speaks to their confidence. There is no point in speculating as to when they will reach Q target, yet I hate to see so much money wasted in windmills that will be abandoned. Solar too will be albatrosses on homeowners roofs as they try to recoup their investment when selling to someone who sees no need for it.

So, it makes no difference to speculate, time will tell and bring the hammer down.

[mvanwink5]

Paper on Z-pinch modeling (link is to the full paper):
Development of five-moment two-fluid modeling for Z-pinch physics
https://aip.scitation.org/doi/10.1063/5.0058420

Plasma physics is a b7tch.