Could Flattened End Magnets Improve Magnetic Mirror Traps?

[FusionJim]

Hello,

Knowing that the loss cone for a symmetrical geometry is also symmetrical, I was thinking has anyone ever tried a magnetic mirror where the central magnets are circular but the end magnets that create the highest B field are instead flattened. Wouldn't a flat coil achieve a stronger B field in the coil center therefore create a better trap? What would happen to the loss cone geometry in such an arrangement ?


Also the plasma density needed for a visible range laser to interact with it is very large into the millions of atmospheres if I calculated correctly , but if the frequency of light is decreased to the lower end of infrared then it seems the plasma density required for the EM radiation to interact with the plasma is much lower , in the couple of hundred atmosphere range.

My second question is this, are there any experiments and research ever done on plugging a magnetic mirror end with focused EM radiation like that of coherent laser light?

 

[phyzguy]

Yes. That's what's done with a baseball coil or with Ioffe bars. This helps a lot. But the results with any magnetic mirror configuration are far inferior to what is being achieved today with toroidal configurations like the tokamak.

 

[berkeman]

Welcome to PF.

has anyone ever tried a magnetic mirror where the central magnets are circular but the end magnets that create the highest B field are instead flattened.

That is what MFTF-B at Lawrence Livermore National Lab was meant to explore:

https://en.wikipedia.org/wiki/Mirror_Fusion_Test_Facility

 

[FusionJim]

Can anyone please comment on the possibility to "plug" a mirror end with coherent infrared radiation of appropriate strength knowing that infrared radiation interacts with plasma starting from couple hundred atmospheres which in theory is achievable i think in a HTS magnet if my information is correct

 

[berkeman]

Can anyone please comment on the possibility to "plug" a mirror end with coherent infrared radiation of appropriate strength knowing that infrared radiation interacts with plasma starting from couple hundred atmospheres which in theory is achievable i think in a HTS magnet if my information is correct

Please post a link to where you are getting this information. We require references in the technical forums in discussions like this.

Also, what level of education do you have so far in Physics and specifically Plasma Physics? Do you have an undergrad background in Math and Physics yet? Do you have access to a technical library? If you have access to a library, check out the classic Plasma Physics textbook by Chen:

https://www.amazon.com/Introduction...olled-Fusion/dp/3319793918/?tag=pfamazon01-20

 

[Vanadium 50]

Can anyone please comment on the possibility to "plug" a mirror end with coherent infrared radiation of appropriate strength

What is "appropriate strength"? I suspect it is unattainable. Can you show us your calculation?

PS I keep getting in touch with my inner Beavis and Butthead. "He said end plug!"

 

[Astronuc]

infrared radiation interacts with plasma starting from couple hundred atmospheres which in theory is achievable i think in a HTS magnet if my information is correct

From where does one find such information? Infrared radiation is rather weak compared to keV ions and electrons.

 

[FusionJim]

@berkeman @Vanadium 50 @Astronuc , seems like i was wrong, i did my search on chatGPT and i know it can be wrong, in theory radiation wavelenghts that interact strongly with given temp and density plasma like coherent IR could plug a mirror end but upon demanding chatGPT a recalculation due to me feeling previous output was wrong it seems one would need a gigawatt range rated beam power to plug a practical plasma pressure within a mirror end,

 

[Alex A]

This might be a useful life lesson both on trusting random pages of the internet and tech fads before they have matured into anything truly useful. ChatGPT is a large language model that operates by estimating the most likely next word ("token") in a sentence. This has a lot in common with many document compression methods - use a model to take out anything predictable and store lossily or losslessly the difference. The better the model the the better the compression.

With a really good model, and in certain limited circumstances it might be possible to operate with no explicit correction data at all. It's perfectly possible that a really really good model would read all of science and internalise the basic rules of our universe. That model could then answer any question from first principles. In practice the large language models appear to learn a lot of rules about sentence structure and a lot of bits of quotes verbatim, and are quite good at assembling sentences that statistically speaking could be an answer. "can be wrong" doesn't really cover it.

Blocking off particles with light is probably not impossible but screams conservation of momentum issues among, frankly, a lot of other problems. With the NIF fusion experiments it's easy to think the light makes the container collapse inwards. Prior to fusion almost exactly as much container momentum explodes outwards as inwards. If you can spare no reaction mass, light is a very inefficient way to apply momentum to anything. Unless you are able to convert matter directly into energy, and anyone that can do that doesn't really need to do fusion.

 

[berkeman]

@berkeman @Vanadium 50 @Astronuc , seems like i was wrong, i did my search on chatGPT and i know it can be wrong, in theory radiation wavelenghts that interact strongly with given temp and density plasma like coherent IR could plug a mirror end but upon demanding chatGPT a recalculation due to me feeling previous output was wrong it seems one would need a gigawatt range rated beam power to plug a practical plasma pressure within a mirror end,

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