Ion Drive Question - Ionization process

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Discussion Overview

The discussion revolves around the operation and feasibility of ion engines, particularly focusing on the ionization process and the conditions under which these engines can function. Participants explore the implications of atmospheric pressure and vacuum environments on ion engine performance, as well as potential applications and advancements in ion propulsion technology.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether a vacuum is necessary for ionization to occur in an ion engine and asks about the highest pressure density that can be tolerated.
  • Another participant argues that higher gas density requires more current/energy to produce ions and suggests that ion engines would not function effectively in an atmosphere due to low thrust.
  • Some participants express skepticism about the feasibility of ion engines operating underwater or in regular atmospheric conditions.
  • There is a suggestion that increasing power could improve thrust, although the accelerating potential is noted as a limiting factor.
  • A participant mentions interest in new ion drive technologies, specifically the DS4G thruster, and expresses curiosity about building and testing their own ion drive.
  • Another participant introduces the DARPA WALRUS program, which may explore atmospheric ion propulsion, and poses a question about using ion thrusters to achieve high rotor speeds.

Areas of Agreement / Disagreement

Participants generally agree that ion engines are not suitable for operation in atmospheric or underwater environments, but there is no consensus on the specifics of vacuum requirements or the potential for atmospheric ion propulsion technologies.

Contextual Notes

Participants discuss various assumptions regarding the operational conditions of ion engines, including the need for vacuum and the implications of gas density on ion production. There are references to specific technologies and programs that may influence future developments in ion propulsion.

Who May Find This Useful

Individuals interested in propulsion technology, aerospace engineering, and experimental physics may find this discussion relevant, particularly those exploring the design and application of ion engines.

Halzman
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I'm fairly familiar with the design and operation of an ion engine, although I do have a two questions in regard to its operation.

1) Normally, an ion engine would be used in space (which is naturally a vacuum) and would output its given thrust. Prior to space flight, is there a need to maintain the vacuum within the chamber where the ionization occurs?

2) When looking at the ion optics, we see that there is 2 perferated sheets, with holes .1 mm range (if i remember correctly) on each sheet. I'm assuming that this would be enough to cause a 'leak' in the chamber, if it was a vacuum to begin with. Does the chamber need to be a vacuum in order for the ionization to occur? If yes, what is the highest pressure density that the chamber can be in order for ionization to occur? I guess more specifically my question is, can an ion engine function in a non vacuum environment? (obviously there would be a problem with weight to thrust, but I'm not concerened with that)

I'm aware that NASA (it could of been the ESA) uses a vacuum chamber to test the ion engine. I'm just curious if it would function in a normal atmospheric pressure environment, and if not, could you balance it out by maintaining a certain vacuum within the chamber.

Just thought of a 3rd question: Would an ion drive work under water?
 
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The greater the density of gas in the ion engine, the higher the current/energy necessary to produce ions, and just ions. The density needs to be reduced to optimize the number of ions as opposed to neutral atoms. Otherwise, one simply ends up with a discharge in a gas.

The aspect is that the thrust is so low that it simply would not work in an atmosphere.

An ion engine like the gas engine described would not work underwater.

One might wish to use an MHD engine instead.
 
Astronuc said:
The greater the density of gas in the ion engine, the higher the current/energy necessary to produce ions, and just ions. The density needs to be reduced to optimize the number of ions as opposed to neutral atoms. Otherwise, one simply ends up with a discharge in a gas.

The aspect is that the thrust is so low that it simply would not work in an atmosphere.

An ion engine like the gas engine described would not work underwater.

One might wish to use an MHD engine instead.

Pretty much expected it not to work in a regular atmosphere/underwater. Just had to ask. However, couldn't the thrust be improved by pumping more power? I know currently were not capable of supply effecient amounts of power to an ion drive (one that's space bound atleast) but is that 1 of the most limiting factors when it comes to thrust?
 
Halzman said:
Pretty much expected it not to work in a regular atmosphere/underwater. Just had to ask. However, couldn't the thrust be improved by pumping more power? I know currently were not capable of supply effecient amounts of power to an ion drive (one that's space bound atleast) but is that 1 of the most limiting factors when it comes to thrust?
The accelerating potential is the limiting aspect.


You may wish to investigate the DS4G thruster technology

http://prl.anu.edu.au/SP3/research/SAFEandDS4G

http://www.esa.int/gsp/ACT/propulsion/safe_thruster.htm

http://www.esa.int/esaCP/SEMOSTG23IE_Expanding_0.html

http://www.abc.net.au/ra/innovations/stories/s1579297.htm
 
Last edited by a moderator:
Astronuc said:
The accelerating potential is the limiting aspect.

You may wish to investigate the DS4G thruster technology

http://prl.anu.edu.au/SP3/research/SAFEandDS4G

http://www.esa.int/gsp/ACT/propulsion/safe_thruster.htm

http://www.esa.int/esaCP/SEMOSTG23IE_Expanding_0.html

http://www.abc.net.au/ra/innovations/stories/s1579297.htm

Thanks, I actually became aware of the new type of ion drive a few days ago. Looks very promising and interesting. I've been interested in building and testing my own ion drive. I have a solid design for the drive itself, as well as all the components. Whether the chamber needs to be a vacuum was the only main question I had. I was aware of the grid errosion problem, so to here about ESA's DS4G was almost a 'breakthrough' on my end. I had always intended to use xenon, as NASA did on DSP.
 
Last edited by a moderator:
thinking outside the box

keep in mind the new ion engine advances, and the DARPA WALRUS program which may use atmospheric ion propulsion. I want to spin a 56' rotor to a tip speed of 210 MPH using 5 small ion thrusters. Is this possible?
 

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