Talk-Polywell.org

What do you all think of this?

https://www.geekwire.com/2022/blue-orig ... ion-energy

Details on their approach are pretty thin, in this article at least. Is this essentially a Polywell, or something different?

The article states that this design utilizes a modified Knight ion trap, which is a type of Kingdon axial ion trap geometry. So definitely not a Polywell. It appears to be more along the lines of Helion or TAE in geometry, as the article mentions that they are using ion guns, which presumably are oriented to fire into the center on either end of the axial trap. Or if guns are off axis, the geometry is somewhat similar to Lockheed Martin's now not-so-compact 'Compact Fusion Reactor'.

A lightweight article about them:

https://www.canarymedia.com/articles/nu ... able-parts

Yeah, not much more information. Certainly nothing that would warrant optimism.

Orbitron


High-Level Concept: High speed ions are electrostatically confined in precessing elliptical orbits around a negatively charged cathode. The ion density is increased by the co-confinement of high temperature electrons trapped by an external weak magnetic field perpendicular to the electrostatic field in a “crossed field” configuration similar to a magnetron microwave device. Crossing elliptical paths of ions provide millions of chances of fusion-relevant collisions before the ion loses energy and is moved out of the interaction space as it falls into the cathode and is removed from the chamber.

History: The Orbitron configuration was invented in 2020 and is under development in Washington State.

Challenges: The interaction space for Orbitron plasma is extremely small for fusion devices, and requires extremely high voltages to trap the ions at fusion relevant speeds. Managing dielectric breakdown and flashover in such a small space is an engineering challenge, and the plasma interactions for glancing beam-beam configurations are not well understood.

Notable Projects: Avalanche Energy

https://www.avalanche.energy/

Yes, I read that and I am still trying to figure out what exactly they think they are doing.

Skipjack wrote: ↑

Fri May 27, 2022 6:06 pm

Yes, I read that and I am still trying to figure out what exactly they think they are doing.

They want to create an electrostatic squeeze of the ions cloud around the cathode.
Imagine a balloon that is pushed under water, the more you go deep, the more the pressure (the charge voltage) will squeeze the balloon and reduce it's volume. As the chance of collision increase with the cube of reduction of the radius of the cloud, is easy to figure out where their selling point is.

This is not different from when good old Archimedes said "give me a lever long enough and I will move the world", which is mathematically
ineccepibile but technically unfeasible.
I estimate that the voltages they will need to create a suitable "pressure" gradient for such a small device to be around the million volt mark.....
Is than enough to look at all the troubles that FocusFusion and ZAP are having with the dielectric breakdown for orders of magnitude lower voltages to understand how scarce are their chances of coming out with a working solution. Unless they have a new and never heard before dielectric insulator able not only to withstand dielectric breakdown at the million volt mark, but also able to prevent flashover, that at those voltages (and in vacuum) is probably more sneaky and troublesome than dielectric breakdown itself.

I personally would not hold my breath for it, also because if such a material existed, ZAP and FF would be making giant leaps in their designs and results.

ZAP and FF have more trouble with the currents than the voltages from what I understand. ZAP is getting their though, AFAIK. FuZE-Q will start operations this summer...
But yeah, high currents in those materials cause some abrasion- problems and those then cause impurities in the plasma. Particularly bad for LPPF.
MIFTI with their stages Z- Pinch also have issues with that, I would assume. They have even higher currents, but their pulses are shorter.

Skipjack wrote: ↑

Sat May 28, 2022 5:57 pm

ZAP and FF have more trouble with the currents than the voltages from what I understand.

Correct.
Flashover issues start to appear in vacuum over 50kV. Under this limit the issues are mainly related to dielectric breakdown (current flow).

ZAP stays safely in the 15/20kV range, so they are far from flashover (voltage) related issues and this should not effect them at all.
Focus Fusion on the other hand is working right at the threshold of that limit (45kV), and that's why they are having a much more hard time.
Flashover issues are mainly focused in the connection point between the electrode and the insulator and are not current dependent but are voltage dependent (similar to a mechanical seal on a pump shaft that is not effected by the pump flow (current) but by the pressure head (voltage)).

Anyhow, as I was saying before, if a material able to withstand flashover at those higher voltages will ever exist, ZAP and FF will greatly benefit from it as it will make their design immediately more competitive allowing both of them to rise their working voltage and/or overcome their actual technological limits.

The article in GeekWire mentions them aiming for 600 kV, which is indeed quite a lot. The University of Wisconsin-Madison IEC has worked on building fusors reaching 300 kV, https://fti.neep.wisc.edu/fti.neep.wisc ... ec2012.pdf. That presentation is already ten years old, so I don't know how high voltages they have reached with their fusors by now.

crowberry wrote: ↑

Mon Jun 20, 2022 7:23 pm

The article in GeekWire mentions them aiming for 600 kV, which is indeed quite a lot. The University of Wisconsin-Madison IEC has worked on building fusors reaching 300 kV, https://fti.neep.wisc.edu/fti.neep.wisc ... ec2012.pdf. That presentation is already ten years old, so I don't know how high voltages they have reached with their fusors by now.

I don't have data on that, but I doubt anyone found yet a practical way to have a clean and stable supply at/or over 50KV. If someone did it should have had quite a lot of publicity in the various meetings as it would benefit practically every single player in the field.

In the contributions of the 20th US-Japan Workshop on Fusion Neutron Sources for Nuclear Assay and Alternate Applications at https://blog.umd.edu/iecf/posterspresentations/ it is reported that the University of Wisconsin-Madision IECF-group managed to their Homer fusor at 200 kV. See these two presentations for the details: https://blog.umd.edu/iecf/files/2018/10 ... vhnwzx.pdf, https://blog.umd.edu/iecf/files/2018/10 ... xpluq4.pdf.

crowberry wrote: ↑

Wed Jun 22, 2022 11:03 am

In the contributions of the 20th US-Japan Workshop on Fusion Neutron Sources for Nuclear Assay and Alternate Applications at https://blog.umd.edu/iecf/posterspresentations/ it is reported that the University of Wisconsin-Madision IECF-group managed to their Homer fusor at 200 kV. See these two presentations for the details: https://blog.umd.edu/iecf/files/2018/10 ... vhnwzx.pdf, https://blog.umd.edu/iecf/files/2018/10 ... xpluq4.pdf.

It is based on a commercial feed-through (used to transfer the charge from point A to point B) which is different from what FF, ZAP and Avalache need. In the research they cleverly optimize the geometry to improve E-fields arching, thus allowing an increase to the feed-through max voltage.

A really interesting research that i didn't know, thanks for pointing it out. Unfortunately as i said is not useful to prevent flashover issues in systems like FF, ZAP and Avalache where the flashover will appear in the point of contact where vacuum, insulator and electrode meet.

LPPF has struggled with arcing in their HV-switches and they describe their plans to mitigate arcing in their latest newsletter. https://www.lppfusion.com/storage/LPPFu ... 0-2022.pdf

crowberry wrote: ↑

Wed Jun 22, 2022 4:46 pm

LPPF has struggled with arcing in their HV-switches and they describe their plans to mitigate arcing in their latest newsletter. https://www.lppfusion.com/storage/LPPFu ... 0-2022.pdf

Happy to see that they are working on a solution. Hopefully they can reach a stable regime at the 45KV in the next test run.