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I’m trying to think of a way to explain how the ion engines in Star Wars ships are able to work within an atmosphere. Ion engines can only work in a vacuum, and don’t have the proper thrust to take off from the ground and my Star Wars writing tries to explain this. What could be done with the ion engine to make it work for both?

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  • $\begingroup$ Just put lots and lots of power behind it. $\endgroup$
    – DKNguyen
    Mar 23 at 0:30
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    $\begingroup$ Hello, we can not help build any worlds attached to existing third party property because those topics can only be answered by experts in those worlds. You can find those people on the Science Fiction and Fantasy stack exchange. Please remove all references to the Star Wars world or this question may be closed. We may be able to help with a generic ion drive if you give your ship and planet specifications. $\endgroup$
    – Vogon Poet
    Mar 23 at 4:36
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    $\begingroup$ Ion engine is used as means of propulsion outside the atmosphere, inside the atmosphere we called it hair dryer. $\endgroup$
    – user6760
    Mar 23 at 6:48
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    $\begingroup$ There are two ways to interpret your question. One: how does a star-wars "ion engine" work in an atmosphere? Two: how might a real-world ion engine work in an atmosphere? The answer to the first is basically "magic" (like everything else in that universe), but in any case it is off-topic on WB.SE. It might be on topic on scifi.stackexchange.com. The answer to the second is "it can't". space.stackexchange.com might elaborate for you, but the question is basically fine for this site. So which do you want to know? $\endgroup$ Mar 23 at 10:13
  • $\begingroup$ This is an ion engine in atmosphere, the advantage over one built for space is it doesn't have to carry bulky tanks of 'atmosphere' to be ionised, the disadvantage 'in atmosphere' is that the thrust is quite weak so it doesn't scale well to full sized craft, in space with no gravity that's not an issue. $\endgroup$
    – Pelinore
    Mar 23 at 12:17

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Electro-aerodynamics

Ion wind propulsion. There's a real world solid state aircraft invented at MIT that makes use of ion thrust, combined with acceleration of ionized air molecules between electrodes,

About nine years ago, Barrett started looking for ways to design a propulsion system for planes with no moving parts. He eventually came upon “ionic wind,” also known as electroaerodynamic thrust — a physical principle that was first identified in the 1920s and describes a wind, or thrust, that can be produced when a current is passed between a thin and a thick electrode. If enough voltage is applied, the air in between the electrodes can produce enough thrust to propel a small aircraft.

https://news.mit.edu/2018/first-ionic-wind-plane-no-moving-parts-1121

There's a video,

https://www.youtube.com/watch?v=boB6qu5dcCw&t=32s

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  • $\begingroup$ THANK-YOU so much $\endgroup$
    – user73829
    Mar 23 at 0:53
  • $\begingroup$ Note that ion-wind propulsion has similarities with an ion engine in the same way that a water turbine has similarities with gas turbines, but you can't really use one to do the job of the other. $\endgroup$ Mar 23 at 10:15
  • $\begingroup$ @StarfishPrime this is not an "ion thruster" as documented by NASA for use in space. But I wonder if your turbine analogue is entirely correct. Both have electrodes. There is no phase transitions involved, both propulsion principles are based on kinetic energy of ions. The difference is the amount of ions involved. In space you'd require only few. The ion wind principle moves more ions and can work in the atmosphere, btw it can be built by anyone rimstar.org/science_electronics_projects/… $\endgroup$
    – Goodies
    Mar 23 at 10:37
  • $\begingroup$ @Goodies both gas and water turbines involve rotating bits with fancy shapes, some fixed bits to keep the flow going the right way, movement of fluids in a preferred direction via impact with rotating blades, y'know. No phase transitions (unless you're getting cavitation in the water one, but don't do that). The difference is the density and viscosity of the medium. The water turbine moves more particles, and can work in the atmosphere, and anyone can build a (poor) one too ;-) $\endgroup$ Mar 23 at 11:02
  • $\begingroup$ @StarfishPrime my remark was not about phase changes in the process, I was referring to the difference in phase when talking gas turbines and water turbines. The only difference between ion thruster and ion wind propulsion is the shape of the electrodes and the amount of ions involved. The exact type of ion propulsion was not specified in the question. $\endgroup$
    – Goodies
    Mar 23 at 11:30
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Same acceleration mechanism. Different mass accelerated.

Kinetic energy is mass * velocity squared. F = mv2 You accelerate mass behind you, the equal and opposite reaction pushes you forward. In space you don't have a lot of spare mass because you are lean and mean. Mean when events warrant, of course. But lean. And so you accelerate mass you brought with: the very little mass of ions. You accelerate them very fast and maximize the v term.

In an atmosphere you have gas. And also molecules of the atmosphere you can use to throw behind you because there are plenty. You do not need to throw them so fast and the neighbors will ask you not to, because those fast ions take the leaves off the landscaping. But you can throw a lot of them, not very fast, maximizing the m term.


And, because you are writing awesome fiction, when things get gnarly you can do the combo. On the planet you can plow mass into your engine and accelerate all that atmospheric gas to relativistic velocities, landscaping and anything else behind you be damned, and it will. There will be flames as the atmosphere behind you is heated to incandescence.

Or when you are in space but you need serious acceleration you can grab anything in your ship not bolted down, throw it into the engine and fire it all out the back as ions. There will again be flames, not as bright, but this time colored according to the elements comprising all the stuff you threw in.

Fiction inspired by this premise: https://www.fictionpress.com/s/3362047/1/Platinum-flames

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