ZAP Energy News

[Giorgio]

They should get in contact with Avalanche fusion and discuss about using their feedthrough technology.
They could than expand their working parameters space to a degree where practical tests would make more sense than investing into simulations.

[Skipjack]

They should get in contact with Avalanche fusion and discuss about using their feedthrough technology.
They could than expand their working parameters space to a degree where practical tests would make more sense than investing into simulations.

They are doing both, but I assume that they want to get simulations in line with the practical results to have a more solid theoretical base.

[bennmann]

https://link.aps.org/doi/10.1103/PhysRevLett.132.155101

Anyone have access to the full article? They mention they have a "basis" for scaling laws now, curious to know their scaling laws for Zap.

[Giorgio]

https://link.aps.org/doi/10.1103/PhysRevLett.132.155101

Anyone have access to the full article? They mention they have a "basis" for scaling laws now, curious to know their scaling laws for Zap.

I do not have the paper and I could not find it so far, but the Fusion power was expected to scale to the 11th power of the pinch current.
If they got confirmation on that is indeed pretty interesting.

I will try to look more deep for someone that has a copy to share.

[Skipjack]

https://link.aps.org/doi/10.1103/PhysRevLett.132.155101

Anyone have access to the full article? They mention they have a "basis" for scaling laws now, curious to know their scaling laws for Zap.

I do not have the paper and I could not find it so far, but the Fusion power was expected to scale to the 11th power of the pinch current.
If they got confirmation on that is indeed pretty interesting.

I will try to look more deep for someone that has a copy to share.

I saw that their scaling laws were indeed confirmed at the > 11th power. The 11th power is what their simulations predict. Their experiments show a somewhat higher scaling, actually, which is interesting in itself (and a reason why they keep working on their simulations).

[Giorgio]

I saw that their scaling laws were indeed confirmed at the > 11th power. The 11th power is what their simulations predict. Their experiments show a somewhat higher scaling, actually, which is interesting in itself (and a reason why they keep working on their simulations).

True, I remember seeing a paper where they actually was speaking of scaling to the 12th power.

[mvanwink5]

Wonderful new paper:

Whole device modeling of the fuze sheared-flow-stabilized Z pinch

https://iopscience.iop.org/article/10.1 ... 326/ad3fcb
(use the pdf link to read this paper)
We had seen earlier models of the Z pinch that talked about the m=0 instability, but the m=1 instability (kink) was not really dealt with. In this paper on their modeling, the inclusion of the m=1 instability is brought in to explain & close the gap between projected results & experimental results. Sheared flow is key for both m=0 & m=1 instabilities, so in the end it all boils down to creation & optimizing that flow profile. To that end I have yet to see any discussion as to how the profile is achieved, the ('secret sauce?' ), but I suppose that would be proprietary.

There has been higher current experiments that I had thought should have led to breakeven Q, some thoughts that there is some 'effective' current vs total current, but I would suggest based on this paper on modeling that the issue is the m=1 kink stability that needs to be introduced that reduces yield. The paper says that once 3-D modeling is used the m=1 instability will show up and not require model hand waving.

I must admit that ZAP Energy is an exciting fusion approach, but I wonder if apparent simplicity will evaporate quickly as current is raised, after all, the radius must shrink dramatically, yet the shear profile must be maintained to avoid instabilities from killing results (at least that is my doubt).

[Skipjack]

Yeah, I am still optimistic about Zap, but slightly less than I am for Helion. They are still my number 2 in the race.

[Giorgio]

I must admit that ZAP Energy is an exciting fusion approach, but I wonder if apparent simplicity will evaporate quickly as current is raised, after all, the radius must shrink dramatically, yet the shear profile must be maintained to avoid instabilities from killing results (at least that is my doubt).

This is exactly the whole point of the issue.
That paper is also (yet again) a good reminder of why you should not trust simulations without supporting experimental data.

Anyhow it seems that they have a clear road to set up a proper testing machine now, we should quickly see if the results will prove or disprove the whole ZAP concept.
Personally, based on last few years advancements in all the related fields, I am feeling optimistic that when higher input values will be supplied the plasma pinch process will self-stabilize as external instabilities influences will become smaller in respect to the pinch values overall strength.

[mvanwink5]

Anyhow it seems that they have a clear road to set up a proper testing machine now, we should quickly see if the results will prove or disprove the whole ZAP concept.
Personally, based on last few years advancements in all the related fields, I am feeling optimistic that when higher input values will be supplied the plasma pinch process will self-stabilize as external instabilities influences will become smaller in respect to the pinch values overall strength.

Yeah, I am still optimistic about Zap, but slightly less than I am for Helion. They are still my number 2 in the race.

I am with SJ, but my reason is because I have no grasp of the knobs to control the pinch stabilizing flow profile. Perhaps if there was a dynamic flow model that ZAP had published, that might assuage my doubts that flow profile requirements will be more demanding, more difficult, with current scaling (I suspect they become more demanding, just cynicism?). Still, this last ZAP paper removed a significant doubt because it threw light on the previously glossed over kink, the m=1, instability. It all boils down to one issue, the flow profile, get a handle on that & everything else points to success.

As for Helion, my view is their issue is just work & time, yet their team looks superb so I expect they will be close to schedule.

[Skipjack]

Yeah, the odd thing with Zap is that their simulations came out worse than their experimental results. That is why they are spending a lot of time on refining their simulations.

[mvanwink5]

Yeah, the odd thing with Zap is that their simulations came out worse than their experimental results. That is why they are spending a lot of time on refining their simulations.

Yes, ZAP's 2D simulations are truly remarkable & extremely encouraging for expediting progress. Further ZAP has confidence that if 3D simulation was performed, they would not have to use the performance fudging, (looking at plasma zones where they suspect kink instabilities (m=1 instabilities) to be present, then backing out those areas from their performance calculations to get simulation results to match experimental results.)

The question in my mind is will the zone of kink instability grow with higher current, & will it grow too fast? Can the flow profile be controlled to deal with this? ZAP does not address this question as this paper is only about simulations.

Perhaps the recent comparison of simulation to experiments that reveals the performance loss due to kink instability will enable future experiment progress?

[crowberry]

In the FIA 2024 report Zap Energy presents its plan for an integrated facility called Century:

Century is the first fully integrated demonstration of three major plant-relevant technologies operating at up to 100 kilowatts of input power. It will validate repetitive pulsed power supplies, plasma-facing circulating liquid metal walls, and technology for mitigating electrode damage in an SFS Z-pinch system operating at high average power.

Century was also presented at the TOFE 2024 conference: Project Century: Zap Energy's 100 kW-Scale Repetitive Sheared-Flow-Stabilized Z-Pinch System with Liquid Metal Cooling, https://www.ans.org/meetings/tofe2024/s ... view-2632/.

I guess we will hear more about this project in due time.

[Skipjack]

Zap just opened another 130 million funding round.
Uri has previously said that they would not publish results until after peer review. But then investors might not need peer review (or have their own reviewers brought in).

https://www.geekwire.com/2024/fusion-st ... ble-power/

[crowberry]

It could be that the additional funding is needed for project Century? The number of people at Zap Energy was listed as 60 in 2022, 140 in 2023 and 150 in the FIA 2024 report, so the last years increase was modest. In addition to salary costs they will have many other expenses to cover. In order to be able to keep moving forward fast with several parallel development paths, more funding is anyway needed.