Electrostatic atmospheric confinement

Calliban · 2024-03-07 09:08:41

Tom's recent discussion on magnets got me thinking about some things.

I have often wondered if it would be possible to confine an atmosphere to a body using an electric field. It would look something like this.

The body would be a hollow metal sphere, filled with metallic powder, which provides capacitance. The material inside the metal sphere is charged positive. Above the sphere, we place a layer of insulative rock. Above this, we have an atmosphere. Above the atmosphere, we have a negatively charged ionosphere. The voltage gradient between the inside of the sphere and the ionosphere, pulls the ionosphere down, exerting enough pressure over the atmosphere to hold it onto the surface. The insulative layer of rock has sufficiently high breakdown voltage to prevent the charges from flowing and cancelling each other. So long as the ionosphere retains its negative charge and the interior its positive charge, the atmosphere remains on the surface of the body.

There is probably a simple reason why this would not work. Even in the ionosphere, there are still neutral atoms that would not be effected by the electric field. And the amount of charge that must be stored to contain an atmosphere in this way would be immense. But can anyone provide a physics based proof for this not working?

In much the same way, a strong magnetic field can be used to contain a plasma. Provided the beta (ratio of magnetic pressure to plasma pressure) is high enough, then charged particles remain trapped. Could a cold plasma, be used to confine a breathable atmosphere to a small body? What sort of power requirement would this entail?

Last edited by Calliban (2024-03-07 09:15:18)

tahanson43206 · 2024-03-07 09:28:11

This post is reserved for an index to post NewMars members may contribute over time.

Best wishes for success with this topic. It may evolve over time, as similar but perhaps presently unknown containment methods are discovered.

You can change the title by editing Post #1 at any time, so if something new does show up, you can merge it without difficulty.

Startrek was full of currently unknown technology, but on the other hand, the hand held communicator is a reality in the Real Universe.

Anti-Matter propulsion and the replicator are still unrealized, but there are already hints of how they might be achieved.

If there is a NewMars reader who would like to help Calliban with this topic, please see the Recruiting topic for procedure.

(th)

Calliban · 2024-03-07 10:15:35

For this idea to work, the breakdown voltage gradient of gas in the ionosphere must be lower than the gas in the atmosphere proper. Some barrier would be needed to prevent the two layers from mixing. As there will be no pressure difference between them, that barrier couod be an inflatable plastic sheet.

kbd512 · 2024-03-07 11:38:32

Calliban,

How does the electrically conductive dust in the Martian atmosphere affect this atmospheric retention concept?

Calliban · 2024-03-07 16:13:05

kbd512 wrote:

Calliban,
How does the electrically conductive dust in the Martian atmosphere affect this atmospheric retention concept?

I wasn't really thinking of Mars, but something much smaller. Suppose we were to make a hollow metal ball 10km in diameter and cover it with a layer of non-conducting rock, like fused silica. Add fine dust to the interior void in the ball to serve as an electrostatic surface. Then establish a charge differential between the interior of the ball and ionised gas above it. Positive ions in the gas will be drawn to the trapped negative charge inside the ball, pulling them to the surface. But the layer of non-conducting rock will prevent transfer of charge provided that voltage gradient does not exceed the breakdown voltage of the rock. So the electrically charged atmosphere should remain stuck to the surface of the ball.

I am pretty certain that this idea won't work. I think the capacitance needed to confine any significant atmosphere would be immense. I am being a bit lazy not getting drawn into the maths. That is what is needed to test the idea.

Even if it could work, creating a world that requires a continuously functioning electric field to maintain its atmosphere, seems like a really bad idea. It is one thing relying on passive features like pressure vessels to keep the air in. Living under an electrostatic forcefield that could disappear if there is a short circuit would keep most colonists up at night.

Last edited by Calliban (2024-03-07 16:18:27)

SpaceNut · 2024-03-07 18:40:35

Artificial Magnetosphere - Electromagnetic Induction

Calliban · 2024-03-11 17:10:25

Plasma becomes increasingly viscous as its temperature rises. A plasma window exploits this effect. It functions rather like a forcefield, trapping plasma in a magnetic field, which prevents air from crossing it due to the viscosity of the plasma.
https://en.m.wikipedia.org/wiki/Plasma_window

The small windows created so far are used in electron beam welding. They are extremely power hungry. But it stands to reason that any body surrounded by a powerful magnetic field in space, will trap solar wind particles. If such a body is then allowed to accumulate an atmosphere, the trapped plasma will form a barrier to escape of air molecules. Obviously, the plasma pressure at the top of the atmosphere must be equal to atmospheric pressure there. Likewise, the plasma pressure must be less than the magnetic pressure or particles will cross the field lines and escape.

One way of doing this would be to put a superconducting ring under the crust of an asteroid. The asteroid surface will provide insulation, allowing the superconductor to remain cold with minimal power consumption. It turns out that thermal conductivity of most solids, declines as temperature approaches 0K.
http://uspas.fnal.gov/materials/19NewMe … re%204.pdf

The weight of the crust will counteract the expansive pressure resulting from the current. Once current is established in the ring, the field will remain stable without additional power. Such a plasma confined atmosphere could remain stable for geological timescales.

Aluminium has a critical temperature for superconductivity of 1.18K. This may be the most suitable material for a superconductor given its abundance.
https://en.m.wikipedia.org/wiki/Superconductivity

Last edited by Calliban (2024-03-11 17:33:12)

tahanson43206 · 2024-03-12 08:19:05

For Calliban re Void's idea ....

While the idea of using a material (ie, glass) seems a bit of a stretch from your opening vision, I am hoping you and Void will see if there is anything that might be done with it ... I understand that the force holding atoms in a solid form (ie, glass) is electrostatic force, although the electrons that facilitate the force are moving like crazy in their orbits.

Thus, with a bit of stretching, Void's suggestion ** might ** be considered as fitting into the concept of the topic.

In any case, I'm hoping the two of you will be willing to see if you can do anything more with Void's suggestion.

A soap film is an example of a structure held together by electrostatic force. A soap film is only a starting point, of course, because one of those does not heal itself if it is penetrated by a sharp instrument. The equivalent structure to hold atmosphere around a solar system object would need to be self-healing, since every few moments a micro-sized object can be expected to pass through the area.

Never-the-less, the two of you may be able to imagine a material that can provide the atmosphere containment service, while being self-healing and perhaps even able to pick up energy from photons passing by, wheher in or out bound.

(th)

Calliban · 2024-03-12 09:06:55

A magnetic field holding a viscous plasma appears to be a better approach than electrostatic confinement.

I ran a few calculations to determine how strong a magnetic field would need to be to confine a 0.3 bar, breathable atmosphere to an asteroid using a plasma window. The magnetic field would contain a plasma, or ionosphere, which would function as a plasma window, preventing air from crossing it. To create this magnetic field, we would run superconducting cables under the surface of the asteroid. How strong would the field need to be? Magnetic pressure is defined as:

PB = B^2/2u0

Where B is in tesla and u0 is the vacuum permeability: 1.26E−6 N.A-2.

Solving the equation yields a value of 0.275T to yield a magnetic pressure of 0.3bar. Suppose we create this field using superconducting wire running under the crust. Yttrium-barium-copper oxide superconductors can support current density up to 90MA/cm2.
https://www.nature.com/articles/s41598-021-87639-4
https://en.m.wikipedia.org/wiki/Yttrium … pper_oxide

Suppose we put the wire 5km under the crust. The plasma-air interface is located some 5km above the crust, to allow for any topography on the asteroid surface. The cables are spaced roughly 5km apart. How much current would each cable need to carry and how thick would it be? For a wire, magnetic flux at distance r is given by:

B = (u0 x I) / (2 x pi x r), where I is current in A.

Solving for r =10,000m and B = 0.275T, gives I of 13.727 billion amps. If the superconducting cable can achieve a current density of 90MA/cm2, then the required cross section of cable would be 152cm2. This translates to a cylindrical cable some 14cm in diameter.

Let us take the example of an asteroid some 100km in diameter. Total surface area wouod be 31,416km2. With cables spaced 5km apart, we need a 1km length of cable for every 5km2 of surface, making for 6283km of cable overall. The equates to some 96,722m3 of superconductor material. The density of this material 6.4g/cm3, giving a total mass of 600,000 tonnes, or 19.46 tonnes per km2. We would need 80,000 tonnes of yttrium to make this much YBCO. This sound like quite a lot. But yttrium is 400x more common than silver. So maybe it could be done.

I would agree that paraterraforming is technically easier. We could support a relatively thin transparent shell using tensile steel members, anchored deep beneath the crust. But it may be less resiliant. Those tensile members have a fatigue life measured in decades rather than centuries. And a meteorite coukd punch a hole in any roof structure. It is much harder to disrupt a cable that is several km beneath the surface.

Last edited by Calliban (2024-03-12 09:14:46)

Terraformer · 2024-07-02 16:32:21

I recall talking about the prospect of retaining an atmosphere with a magnetic field many years ago. Possibly in the terraforming Ceres discussion. I'm interested in how much of an atmosphere we could get retain in such a way -- could Ceres keep a few mb for radiation and micrometeorite protection?

SpaceNut · 2024-07-02 19:15:27

Yes, magnetic fields have been talked about as a for mars atmospheric retention. Its is also similar to the radiation protection that I proposed for the Large ship....

Calliban · 2024-07-03 12:04:14

Terraformer wrote:

I recall talking about the prospect of retaining an atmosphere with a magnetic field many years ago. Possibly in the terraforming Ceres discussion. I'm interested in how much of an atmosphere we could get retain in such a way -- could Ceres keep a few mb for radiation and micrometeorite protection?

The answer depends upon the magnetic field strength. To contain a plasma, magnetic pressure must exceed plasma pressure. The higher the beta (the ratio between the two) the lower the rate of leakage. Ions will tend to leak out at the poles. And collisions between ions give some enough energy to escape. But a strong magnetic field generated by superconductors, could retain enough atmosphere to be breathable by humans. How long an atmosphere could be retained in this way I don't know.

Terraformer · 2024-07-03 12:15:38

Here is the cringe thread I started when I joined.

(In my defence I was barely even a teenager at that point)

A lot of posts from Antius about magnetic fields. The idea isn't plasma pressure, but atmosphere recovery by recycling ions. IDK how much ionisation we can expect though.

Terraformer · 2024-07-05 14:54:45

Given how abundant iron is, could we add a magnetic core of some kind to such systems to help shape the field and reduce the energy requirements?

SpaceNut · 2024-07-05 16:31:06

A parabolic loop that extends from the surface vertically that is electrically charge would rise the field above the planet for sure.

Magnetic Field of Mars

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

https://core2.gsfc.nasa.gov/research/pu … _proof.pdf

Calliban · 2024-07-28 16:00:22

Reading about the use of mini magnetosphere for space radiation protection.
https://earthweb.ess.washington.edu/spa … elding.pdf

The concept intrigues me more and more. Suppose we place a superconducting ring around an asteroid and induce a current up to but not exceeding critical current density. The solar wind will inflate the magnetic field, though will not increase local field strength. But solar wind ions will inflate the magnetosphere until local plasma pressure is ~ the magnetic pressure.

Plasma is viscous and can be used to contain an atmosphere at pressures up to 9bar.
https://en.m.wikipedia.org/wiki/Plasma_window

With the field in place and filled with solar wind plasma, it should be possible to inflate an electrically neutral atmosphere beneath it. The magnetosphere will extend many thousands of km into space and has enough magnetic moment to deflect charged particles from solar flares and cosmic rays.

The use of superconducting magnets would appear to provide a universal terraforming tool, which is relatively easy to set up. Once the loop is in place and charged, the solar wind does the work of providing the plasma pressure.

Last edited by Calliban (2024-07-28 16:07:32)

Void · 2024-07-28 17:45:34

In "Index» Terraformation» Hill Sphere and Orphan Shells (And Bubble Worlds).", I have a similar interest.

But I am interested in mining the solar wind, for Hydrogen for making water and for the Helium. I am aware that if Fusion becomes practical, then it may create Helium also.

I know that Helium is in short supply. But I think if major new supplies were to appear, then human activities would learn to use more. That might raise standards of living.

But I lack a way to understand proportion here. Can you figure out what an accumulation rate might be over time for a sized collector, if it is 100% efficient?

As you must know I lack that ability.

Done

Calliban · 2025-02-20 10:12:32

This article is nearly 20 years old, but is an interesting idea.
https://www.newscientist.com/article/dn … mars-trip/

The scientist proposes extending a superconducting mesh around a spacecraft and inflating it with ionised hydrogen. The current induced in the plasma would create a powerful magnetic field, deflecting cosmic rays during an Earth-Mars transit.

I wonder if something like this could be built as a static installation around an asteroid? Metal ions sourced from the asteroid itself could be used to fill the plasma bubble. Once it reaches a certain radius, collisions with solar wind ions and solar UV will help to maintain its temperature and ionisation.

kbd512 · 2025-02-20 13:04:29

Calliban,

My surmise is that this plasma field has to be significantly denser than Earth's Van Allen belts and upper atmosphere due to scaling and the power input to maintain the field, because it has to be dense enough to produce collisions with incoming relativistic ions for it to be effective.

After a plasma sheath has been inflated, how does one communicate with the people or robotic equipment inside this proto-planet space station / mining operation?

Are there optical devices capable of penetrating through the plasma, perhaps X-ray laser communications?

If not, or if the signal distortion from plasma interaction is too great over vast distances, what about a laser comm relay satellite in orbit around it?

When we want to receive visiting spacecraft for transfer of crew / cargo / mined resources from the asteroid, will we have any electrostatic discharge or heating issues that might mess with its onboard systems?

Terraformer · 2025-02-20 16:20:19

Been playing X2 and X3 (Reunion) (space 4X games) recently, and it got me thinking about the idea of the gates collecting a (very tenuous) atmosphere that results in ships having maximum speeds and continuos thrust and other such tropes.

Anyway, the relevance here is, what might travel be like within such a magnetosphere containing say an atmosphere equivalent to 60km here on Earth? Pretty much vacuum from a human POV, but that's still enough drag that nothing can orbit there. There would be far more mass available for an ionocraft such as the dipole drive to make use of.

Then I got thinking about the highways of X4 and started to wonder about linking magnetospheres into a torus...

Calliban · 2025-02-20 16:22:59

kbd512 wrote:

Calliban,
My surmise is that this plasma field has to be significantly denser than Earth's Van Allen belts and upper atmosphere due to scaling and the power input to maintain the field, because it has to be dense enough to produce collisions with incoming relativistic ions for it to be effective.
After a plasma sheath has been inflated, how does one communicate with the people or robotic equipment inside this proto-planet space station / mining operation?
Are there optical devices capable of penetrating through the plasma, perhaps X-ray laser communications?
If not, or if the signal distortion from plasma interaction is too great over vast distances, what about a laser comm relay satellite in orbit around it?
When we want to receive visiting spacecraft for transfer of crew / cargo / mined resources from the asteroid, will we have any electrostatic discharge or heating issues that might mess with its onboard systems?

That is a good question. The plasma is electrically conductive, so will be impenetrable to radiowaves with a wavelength greater than the mean distance between the ions. Unless the plasma is very dense, visible and infrared light will pass through it and maybe some of the higher frequency microwaves.

The deflection of cosmic rays is the result of the magnetic field created by the plasma current, rather than direct shielding from the plasma particles. Most cosmic rays are charged particles. Compared to atmospheric gas, the plasma will be diffuse due to its high temperature.

The magnetic field could certainly interfere with spacecraft systems. Any velocity that the spacecraft has w.r.t the magnetic field, will induce eddy currents in its hull. I don't know how significant a problem this would be. But the plasma cloud would definitely complicate communication. Likely, coms would need to be via laser to a satellite outside the plasma field.

The idea presented in the article is similar to the M2P2 idea of using an inflating plasma bubble as a magnetic sail. But in the case of M2P2, the plasma was released outside of the ship and was not contained in a mesh. A relatively small solenoid onboard the spacecraft would trap the plasma. A current would be established within the plasma, reinforcing and inflating the magnetic bubble.

One thing I am not sure about is whether this could actually be used to contain some kind of atmosphere. The plasma window concept is able to seperate Earth's atmospheric pressure from a vacuum. Plasma becomes increasingly viscous as temperature rises and it tends to push other matter out of it. This is now used to carry out electron beam welding. It can reportedly maintain a vacuum against a pressure up to 9bar. But the plasma window is a tiny aperture at the centre of a cyclindrical solenoid. If a superconducting magnetic coil is able to trap plasma around an asteroid, does that imply that we could establish a breathable atmosphere on its surface, trapped beneath a magnetically confined plasma?

If the plasma can be inflated by establishing a current within it, then we could wrap a relatively modest superconducting cable around the circumference of an asteroid and let solar wind fill it up with hydrogen ions. When plasma density and pressure is sufficient, release oxygen and build a trapped breathable layer beneath the plasma. I cannot quite believe that this would work. But it is a question for a physicist I think.

Last edited by Calliban (2025-02-20 16:57:19)

Calliban · 2025-02-20 17:24:34

This is a crude image of what I had in mind.

The local plasma pressure would be a function of the magnetic pressure produced by the superconducting coil and any current induced in the plasma. Plasma pressure would increase until it reached the surface of the asteroid, where the local B is greatest. If the plasma is viscous and tends to exclude a colder fluid, an atmosphere can be trapped between the plasma and the asteroid surface. Maybe that atmosphere could be breathable?

The energy needed to keep the plasma hot would be provided by solar wind particles that would be trapped by the field over a huge radius. As they spiral down the field lines, they collide with trapped plasma particles, heating them. The superconducting coil has zero electrical resistance and will sustain a magnetic field indefinitely once established.

My question is, could this work in real life? Could we take a superconducting loop to, say, a 10km diameter asteroid and use it to establish a breathable trapped atmosphere on the surface? There must be some reason why this won't work in real life.
******

There are number of potential problems with this idea that I can see.

1. The oxygen layer will be much denser than the plasma that is confining it. Although plasma is viscous and will tend to push matter out of it, there is the possibility of Rayleigh-Taylor instability.
https://en.m.wikipedia.org/wiki/Rayleig … nstability

2. The hot plasma will conduct heat into the oxygen layer. This would gradually heat up the breathable air space. The oxygen will transfer heat to the ground which will then radiate heat into space. The question is whether this will occur at a temperature that humans can tolerate.

3. Radiation from the plasma may be a problem. As electrons in the plasma collide with charged ions, they will release UV and soft x-rays. This could be a problem to anyone standing beneath the plasma without a space suit. At temperatures <1KeV, the radiation won't be highly penetrating. But it may be a problem for bare skin. If the hydrogen plasma is contaminated by oxygen ions, the effect will be worse.

4. Radiated heat from the plasma could be a problem. It will heat everything immersed within the plasma. As with conducted heat, it isn't certain that the equilibrium temperature of the body immersed in the plasma will be livable for humans.

5. Plasma will tend to escape from the magnetic field along the field lines closest to the poles. If this escape is dominated by solar wind ions, then it won't be a problem. But if it includes oxygen, then it is a loss that needs continuous makeup. Again, I cannot quantify the problem.

For bodies that are far from the sun, the radiated heat from the plasma could in fact be an asset. The magnetic field is collecting energy from the solar wind over a vast area. As solar wind particles deposit their energy into the trapped plasma, it will radiate heat that will keep the asteroid warm. The question is whether it will radiate too much heat to be tolerable for people on the asteroid?

Last edited by Calliban (Yesterday 04:06:21)

Terraformer · Yesterday 12:21:13

Tbh I suspect its the power loss from radiation and conduction that would kill this. Its possible that it would be manageable for very thin (but still useful) atmospheres, such as needed to handle micrometeorites, or for capping the atmosphere on low gravity worlds such as Ceres. If used to deal with atmospheric escape, it may be that we'd still have years of atmosphere left to effect a fix should the system fail, the field is there to extend those years indefinitely.

Could prove useful in the Saturn system. Six worlds comparable to Ceres. Uranus has five.

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Electrostatic atmospheric confinement

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