# Helmholtz coil based air thruster?

by GreenAce92
Tags: based, coil, helmholtz, thruster
 Mentor P: 9,593 If you ionize air, you have a plasma with positive and negative charges. The total force on any part of air would be zero, unless you get significant charge separation - and what do you do with the separated charges afterwards? In the frame of the coils (=frame of the airplane/rocket), a magnetic field will not increase the velocity of charges, where do you expect thrust if your flow in and out goes in the same direction? Even if you somehow manage to get any (!) acceleration, where is the advantage compared to a simple propeller? No moving parts, fine, but what about the efficiency? Ionization is a very expensive process in terms of energy.
 P: 37 Just a random guess, what about a dual filter that separates each "charges" then an appropriate magnetic field is applied to that charge? What do you mean that my "flow in and out" goes in the same direction? I thought I had depicted that the "atmosphere" to be ionized comes in from the left side then supposedly after being accelerated goes to the right direction. Yes I understand what you're saying. I just had a hard time figuring out how people would make "electric jets" without the process of igniting the compressed air with a fuel of some sort I am really glad for your response. As I said this isn't really my thing (maybe I didn't say that) it was a random thought/idea and thus is a good example of diffidence not being a good thing. Well I suppose for most people who are not geniuses.
Mentor
P: 9,593

## Helmholtz coil based air thruster?

 Just a random guess, what about a dual filter that separates each "charges" then an appropriate magnetic field is applied to that charge?
I doubt that you will get two different air flows. Probably electrons landing on an electrode, and positively charged air remaining.

 What do you mean that my "flow in and out" goes in the same direction? I thought I had depicted that the "atmosphere" to be ionized comes in from the left side then supposedly after being accelerated goes to the right direction.
=> air moves to the right in both cases
 P: 37 So are you trying to say that this sort of a propulsor works primarily by action and reaction? Like a rocket?
 Mentor P: 9,593 It is simple: you cannot violate momentum conservation. To get thrust in one direction, you have to accelerate matter in the opposite direction.

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