Ion craft using magnetic field instead of E-field

Click For Summary

Discussion Overview

The discussion revolves around the concept of using magnetic fields to propel charged ions in a cylindrical setup, exploring the feasibility of this approach compared to traditional ion thrusters that utilize electric fields. Participants examine the behavior of charged particles in magnetic fields and the implications for generating thrust.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant proposes a design involving a vertical cylinder with charged ions flowing down, questioning how to determine their velocity and whether this would generate enough force to lift the cylinder.
  • Another participant points out the complexity of charged particle motion in magnetic fields, referencing the Lorentz Force and suggesting that ion thrusters produce minimal force.
  • A participant requests a sketch of the proposed setup to better understand the design.
  • The original poster describes the setup as a toilet paper tube with wire wrapped around it to create a coil, expressing interest in predicting the speed of the ions based on the current in the coil.
  • One participant argues that in the proposed configuration, ions would either experience no force or be pushed into the walls of the tube, questioning the acceleration of ions along the tube.
  • Another participant reinforces that the magnetic field is parallel to the particle velocity, indicating that no force would act on the ions, and suggests studying electromagnetism and ion thrusters for better understanding.
  • There is a challenge regarding the expectation of a downward force on ions, especially if they are at rest, with some participants asserting that no such force exists.
  • One participant concludes that using an electric field seems necessary to accelerate the ionized particles, noting that magnetic fields do not provide the required push.
  • Further discussion includes thoughts on using electric fields, with a participant mentioning volt converters and questioning the optimal length of the electric field in relation to the setup.
  • Another participant warns against using the converters due to safety concerns, suggesting a lack of necessary knowledge for safe operation.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the feasibility of using magnetic fields for propulsion, with significant disagreement on the expected forces acting on the ions and the necessity of electric fields for acceleration. The discussion remains unresolved with no consensus on the proposed approach.

Contextual Notes

Participants highlight limitations in understanding the principles of electromagnetism and the behavior of charged particles in magnetic fields. There are unresolved questions about the design's effectiveness and safety concerns regarding the proposed use of electrical components.

curiosG
Messages
4
Reaction score
0
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?
 
Physics news on Phys.org
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.
 
Do you have a sketch of the proposed setup?
 
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.
 
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.
 
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.
 
  • Like
Likes   Reactions: Ibix
curiosG said:
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.
 
Ibix said:
ions entering the tube will either experience no force or be pushed into the walls
marcusl said:
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.
 
So it sounds like I can't 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
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
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.
curiosG said:
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.
 
  • Like
Likes   Reactions: Nik_2213
  • #12
mfb said:
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:
 

Similar threads

  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 12 ·
Replies
12
Views
664
  • · Replies 20 ·
Replies
20
Views
5K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 16 ·
Replies
16
Views
2K
  • · Replies 3 ·
Replies
3
Views
714
  • · Replies 6 ·
Replies
6
Views
2K