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Author Topic: Can an electromagnet repel ionized air molecules?  (Read 13391 times)

Offline evan_au

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Re: Can an electromagnet repel ionized air molecules?
« Reply #25 on: 31/03/2015 11:46:20 »
Quote from: starwarsmat
assuming only one electron of charge is added to each molecule
It is true that something like sulphuric acid can achieve very high levels of ionisation - but only because each ion is surrounded by other ions of the opposite polarity, keeping the liquid electrically neutral at the level of a 100 molecules or so.

However, adding the same charge to every molecule represents an enormous charge on each milliliter of air! It would certainly move a soccer ball!
However, that charge density is not practical, as the equipment would blow itself apart due to electrostatic repulsion.

The Millikan experiment was able to measure the effect of single electrons on a tiny droplet of oil - but that is one electron in a billion billion molecules (plus a couple more orders of magnitude).

So think small - a traditional piece of equipment in electrostatic demonstrations was a pith ball - very small, very light, but big enough to be seen with the naked eye. You can move it by rubbing two different insulators together, and holding it close.
 

Offline starwarsmat

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Re: Can an electromagnet repel ionized air molecules?
« Reply #26 on: 01/04/2015 02:51:42 »
would there be a way to increase the charge density significantly without a massive increase of voltage such as a series of electrodes in a circle in the tube or would each electrode need a separate voltage source to have maximum corona discharge to increase the charge density.

something like this but less crude.
« Last Edit: 03/04/2015 03:09:25 by starwarsmat »
 

Offline wolfekeeper

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Re: Can an electromagnet repel ionized air molecules?
« Reply #27 on: 11/04/2015 20:23:15 »
It's definitely possible to move ionised air around using magnetic fields.

Ionised air is called a 'plasma' and plasmas are routinely moved using magnetic fields.

Trouble is, air is very difficult to ionise, unless you use low pressures.

It would be fairly easy to do this in the ionosphere, much, much, much harder at ground level.

You might be able to do it with argon, I think that ionises at STP. I think it was argon, one of the noble gases anyway, but not ordinary air.
 

Offline PmbPhy

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Re: Can an electromagnet repel ionized air molecules?
« Reply #28 on: 28/04/2015 04:08:25 »
Quote from: starwarsmat
My project is to create a device that will accelerate the air ions in one direction and to calculate their acceleration.
It's impossible for a magnetic field to have that effect on anything. Doing so would increase the objects kinetic energy which means that work was done on it. It's a well-known fact that a magnetic field cannot do work on a charged particle.
 

Offline wolfekeeper

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Re: Can an electromagnet repel ionized air molecules?
« Reply #29 on: 28/04/2015 12:59:25 »
Maybe not a single charge, but I'm pretty sure that varying magnetic fields can accelerate a plasma.
 

Offline Colin2B

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Re: Can an electromagnet repel ionized air molecules?
« Reply #30 on: 28/04/2015 14:47:57 »
Maybe not a single charge, but I'm pretty sure that varying magnetic fields can accelerate a plasma.
Problem is the OP is having difficulty generating ionised air, let alone mucking about with a plasma.
He is looking for something simple, but hasn't quite grasped how much charge would be needed to move a football.
 

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Re: Can an electromagnet repel ionized air molecules?
« Reply #30 on: 28/04/2015 14:47:57 »

 

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