Ion craft using magnetic field instead of E-field

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Main Question or Discussion Point

Hello folks,

I did some research and I know a charged particle in a coil magnetic field travels along the lines of the coil.

My thoughts are having a vertical cylinder and having charged ions flow down.

1. How can I figure out how much velocity the charged ions would have.
2. Would it generate enough force to float the cylinder up?
 

Answers and Replies

  • #2
marcusl
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Im afraid your question is too vague to answer as is, and your grasp of physical principles seems weak. The motion of charged particles in a magnetic field is complicated since they experience a transverse force given by a vector cross product. Look up Lorentz Force. There are ion thrusters used for spacecraft but the force they produce is generally minuscule. Look up ion thruster. Then if you have a specific, well-defined question, we can try to answer it.
 
  • #3
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Do you have a sketch of the proposed setup?
 
  • #4
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No sketch but think of a toilet paper tube with wired wrapped around to make the coil. As it is documented - a coil of wired with a charge makes a magnet and in the cavity of the tube charged particles will be forced downward.

Just like other ion crafts a thin wire will ionate the air above the tube and the ions will flow down.

Just want to know how can I predict the speed of the ions, probably relational to the amount of amps in the coil?

Thanks.
 
  • #5
Ibix
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Magnetic fields apply a force to charged particles perpendicular to the field lines and the particles' velocities. If I understand your design correctly you will have magnetic field lines running along the tube and ions flowing along the tube. In this configuration, then, ions entering the tube will either experience no force or be pushed into the walls. They won't be accelerated along the tube, unless I'm misunderstanding something.
 
  • #6
marcusl
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The magnetic field you are considering is parallel to particle velocity so the ions experience no force, as ibix says, so your cylinder will not experience a force either. Even if you change geometry to produce a force, magnetic fields are "conservative" so cannot add energy to a moving charged particle. Its energy is determined only by the ion generator. I strongly suggest studying some E&M as well as info on ion thrusters to aid you in understanding.
 
  • #7
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and in the cavity of the tube charged particles will be forced downward.
Why do you expect a force downward? Especially (but not limited to) ions at rest?

There is no such force.
 
  • #8
Ibix
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ions entering the tube will either experience no force or be pushed into the walls
Even if you change geometry to produce a force, magnetic fields are "conservative" so cannot add energy to a moving charged particle.
D'oh! Modifying my previous answer, ions moving not-quite-parallel to the field will spiral around the field lines, not get pushed into the walls.
 
  • #9
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So it sounds like I cant escape not using an e-field to accelerate the ionized particles.

Now using an e-field the m/s on the particles are in the tens of thousands of not more but once the particles hit the other side of the field they are neutral. I wanted to use a M-field so I could recycle the charged particles but sounds like m-fields don’t push the particles.

Thanks folks -
Next step is how can I continuously accelerate the particles after it passes thru?
 
  • #10
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More thoughts using the e-field.

I have some volt converters I bought on amazon, it takes 9volts and turns it into 1M. I’m sure at the exspense of amps.

Using one these converters what’s the optimal length of the e-field? Again thinking back to the toilet paper roll, is that too long? Too short?
 
  • #11
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As long as you keep the particles around they don't provide thrust. You have to kick them out at the bottom. A higher speed will give a higher specific impulse but need more energy per thrust.
I have some volt converters I bought on amazon, it takes 9volts and turns it into 1M. I’m sure at the exspense of amps.

Using one these converters what’s the optimal length of the e-field? Again thinking back to the toilet paper roll, is that too long? Too short?
Don't use them. You do not have the necessary knowledge to do it safely.
 
  • #12
berkeman
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Don't use them. You do not have the necessary knowledge to do it safely.
This is probably a good time to close this thread as potentially dangerous. Thanks to all who contributed. :smile:
 

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