Plasma "Balloon": is it possible?

[Eccentrus]

IDK if it's fits here, but I can't find somewhere else more fitting so here's the deal:

"We" (I assume everyone here has studied physics in some part of their life) know that a "lighter than air" aircraft can fly because they are literally lighter than air, and can fetch more speed from the kinetical energy that is temperature than the ambient atmosphere (as in the case with a hellium balloon, which would fall in Jupiter :lol, or because we injected them with kinetical energy (heat) ourselves, like in a hot air balloon, so I somehow think of mixing them up, and came up with a hot plasma balloon, and of course it would be Hydrogen plasma, which will, if its temperature is kept in the "plasma region", fly to the edge of the atmosphere, but, as in a Hellium Zeppelin, we'll need to contain it so it can produce lift to an aircraft, but what puzzles me is that, can we make the contraption compact and light enough so that it can fly? or will we need a handwavium to make this work? (yes, I know about superconductors and the like, but one is ignorant about the mass and the energy required to make the plasma stay as plasma)

 

[Moach]

i imagine something like this could be powered by a fusion core (yes, kinda like the sun)... the "fusioning" plasma would be contained by a magnetic shell - powered by the core itself, which by it's own heat, becomes so much lighter than air that the whole apparatus simply floats (???)

of course... if you have a fusion reactor going on, you don't really need buoyancy to gain lift... as you'd have so much energy that you could bring it aloft simply by "brute force"


of course... this is mostly sci-fi... i'm running low on my "real science" supply here :shrug:

 

[Usquanigo]

Wouldn't a vacuum be better? Since buoyancy is a result of displacing an amount of something (air, water, etc) with a lighter "something" (say, air in water, or helium in air), the ultimate expression is to displace the medium with a big ball of nothing.

The downside is you have to make the container strong enough to withstand the pressure of the medium you're floating in, and that can make it heavy (which is why we haven't done it yet), the upside is that you don't have to worry about dealing with the heat of plasma.

 

[Moach]

correct!
you really can't get any less dense than vacuum :hmm:

but how does one "fill" a baloon with nothing?

perhaps a beam-structured geodesic frame could hold a unimaginably strong and lightweight baloon full of "empty"... if it such baloon can be kept from collapsing under the external pressure - it would float like no other thing on this earth :blink:

 

[Usquanigo]

You'd have to either just hook it up to a vacuum pump, or you could do it in space, then bring it back down. hehe

 

[Moach]

another option is to tie stretcher cables to the nodes on the structure, connecting to the completely deflated balloon, then with the pressure seals in place, stretch it full of nothing...

would require a LOT of tugging power to displace all that amount of air... but it could be done slowly, i guess :hmm:

 

[Usquanigo]

I suspect that any such device would have to be either solid, or extremely internally braced (so that there is little square footage of material to stretch).

Any sort of rubber, natural or synthetic, would rip under that sort of strain.

 

[tori]

What you need is a perfect sphere and a perfectly homogeneous ideal gas atmosphere. Then all the pressure will manifest itself as compressive loading on the material the sphere is made of, so the only limitation will be the material's compressive strength. Theoretically (I guess at absolute zero to factor out any random particle movement) you could do with a single layer of atoms in your envelope, so it would be light no matter what you make it out of.

In real world... well. You'd have to stage it. Use a hydrogen-filled balloon to do the initial lifting. Then, as you rise, start venting the operating gas to maintain a certain amount of lift with the least amount of mass as possible. Use a black balloon and fly during the day to get some extra buoyancy (warm hydrogen lifts more).

 

[Eccentrus]

well, as far as my logic brings me, a balloon of vacuum will not fly (well, I don't have proof yet, so let us go with the classical Law of Archimedes to solve this problem)

the question is also not of a balloon of vacuum, but if anyone want to do it, we have to use nanotechnology, with those "Jupiter atmosphere" grade balloons made of carbon nanotubes which were spun around in such a manner so that it also have tiny beams criss-crossing here and there to provide support,

 

[tori]

Archimedes agrees that a vacuum balloon is a solid (and unfeasible) idea.

 

[Scarecrow]

"We" (I assume everyone here has studied physics in some part of their life) know that a "lighter than air" aircraft can fly because they are literally lighter than air, and can fetch more speed from the kinetical energy that is temperature than the ambient atmosphere (as in the case with a hellium balloon, which would fall in Jupiter :lol, or because we injected them with kinetical energy (heat) ourselves, like in a hot air balloon

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well, as far as my logic brings me, a balloon of vacuum will not fly (well, I don't have proof yet, so let us go with the classical Law of Archimedes to solve this problem)

I'm not convinced you understand why a lighter than air vehicle flies. Kinetic energy in the form of heat has (almost) nothing to do with it. It's exactly the same principle as an object floating or sinking in water. If an object is more dense than the fluid it is in (air, water, whatever), then it will sink, because the fluid will move around to bring the whole system to a low potential energy state (one with heavy objects lower). If an object is less dense than the fluid, the mass of the fluid taking up the same volume as the object is greater than the mass of the object itself, so the fluid is the heavy thing that sinks, and it pushes the object out of it's way, making it float higher.

The reason a hot air balloon needs to be hot is because hot air takes up more space than cold air (the molecules need more space to bounce around), and is therefore less dense. Interestingly, this is also why hot air rises, cold air sinks, and we get interesting things like rain storms and tornados.

Therefore, the only reason a vacuum balloon is impractical is that we don't have strong enough materials to create a sizable object that can withstand 1 atmosphere of pressure and simultaneously be lighter than the volume of air it displaces.