You can use magnetic instead of electrostatic forces as the force holding the surface out against air pressure. One disadvantage is that you need superconducting cables fairly spread out* over the airship’s surface, which imposes some cooling requirements. An advantage is square-cube law means it scales well to large size. Another disadvantage is that if the cooling fails it collapses and falls down.
*technically you just need two opposing rings, but I am not so enthusiastic about draping the exterior surface over long distances as it scales up, and it probably does need a significant scale
To hold the surface out, you need to have a magnetic field tangent to the surface. But you can’t have a continuous magnetic field tangent to every point on the surface of a sphere. That’s a theorem of topology, called the Hairy Ball Theorem. So there has to be some area of the ball that’s unsupported. I guess if the area is small enough, you just let it dimple inwards in tension. The balloon would be covered in dimples, like a golf ball.
Yes, for that reason I had never been considering a sphere for my main idea with relatively close wires. (though the 2-ring alternative without close wires would support a surface that would be topologically a sphere). What I actually was imagining was this:
A torus, with superconducting wires wound diagonally. The interior field goes around the ring and supports against collapse of the cross section of the ring, the exterior field is polar and supports against collapse of the ring. Like a conventional superconducting energy storage system:
I suppose this does raise the question of where you attach the payload, maybe it’s attached to various points on the ring via cables or something, but as you scale it up, that might get unwieldy.
I suppose there’s also a potential issue about the torque applied by the Earth’s magnetic field. I don’t imagine it’s unmanageable, but haven’t done the math.
My actual reason for thinking about this sort of thing was actually because I was thinking about whether (because of the square-cube law), superconducting magnetic energy storage might actually be viable for more than just the current short-term timescales if physically scaled up to a large size. The airship idea was a kind of side effect.
The best way I was able to think of actually using something like this for energy storage would be to embed it in ice and anchor/ballast it to drop it to the bottom of the ocean, where the water pressure would counterbalance the expansion from the magnetic fields enabling higher fields to be supported.
You can use magnetic instead of electrostatic forces as the force holding the surface out against air pressure. One disadvantage is that you need superconducting cables fairly spread out* over the airship’s surface, which imposes some cooling requirements. An advantage is square-cube law means it scales well to large size. Another disadvantage is that if the cooling fails it collapses and falls down.
*technically you just need two opposing rings, but I am not so enthusiastic about draping the exterior surface over long distances as it scales up, and it probably does need a significant scale
To hold the surface out, you need to have a magnetic field tangent to the surface. But you can’t have a continuous magnetic field tangent to every point on the surface of a sphere. That’s a theorem of topology, called the Hairy Ball Theorem. So there has to be some area of the ball that’s unsupported. I guess if the area is small enough, you just let it dimple inwards in tension. The balloon would be covered in dimples, like a golf ball.
Yes, for that reason I had never been considering a sphere for my main idea with relatively close wires. (though the 2-ring alternative without close wires would support a surface that would be topologically a sphere). What I actually was imagining was this:
A torus, with superconducting wires wound diagonally. The interior field goes around the ring and supports against collapse of the cross section of the ring, the exterior field is polar and supports against collapse of the ring. Like a conventional superconducting energy storage system:
I suppose this does raise the question of where you attach the payload, maybe it’s attached to various points on the ring via cables or something, but as you scale it up, that might get unwieldy.
I suppose there’s also a potential issue about the torque applied by the Earth’s magnetic field. I don’t imagine it’s unmanageable, but haven’t done the math.
My actual reason for thinking about this sort of thing was actually because I was thinking about whether (because of the square-cube law), superconducting magnetic energy storage might actually be viable for more than just the current short-term timescales if physically scaled up to a large size. The airship idea was a kind of side effect.
The best way I was able to think of actually using something like this for energy storage would be to embed it in ice and anchor/ballast it to drop it to the bottom of the ocean, where the water pressure would counterbalance the expansion from the magnetic fields enabling higher fields to be supported.