How they work: More detail

The last article was more of an overview of an ion thruster. Now I'll tell you how they really work, at the molecular scale.
First, definitions:
    Ionization: "Ionization is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons to form ions, often in conjunction with other chemical changes." ~Wikipedia, see sources, https://en.wikipedia.org/wiki/Ionization

    Plasma: Ionized (see above) gas.


In an ion thruster, the high voltage between the positive and negative electrodes (see previous post for the diagram) rips the electrons off the gas atoms (usually xenon, a gas similar in properties to neon), ionizing them. Gas that is ionized this way has a positive charge, since the electrons that were ripped off were negative. If something is charged it acts like a magnet, and that is exactly what the gas molecules do, pushing each other apart and causing the gas to expand.
Since magnetic fields can be used to move ions, electromagnets are used to direct and accelerate the plasma out the back of the thruster. This is also helped along by the fact that the backward electrode on the thruster is negative, and therefore attracts the positively ionized plasma (like magnets).

What is ion propulsion?

Ion thrusters are an efficient but slow form of propulsion, that could theoretically be used to travel extremely long distances in space.
They use very high voltage to ionize gas, basically turning it into a bunch of magnets. Since magnets attract and repel each other, electromagnets are used to direct and accelerate the ionized gas (plasma) out the back of the thruster. If the thruster is mounted on a spacecraft, this can be used to traverse extremely large distances at high speeds. Ion thrusters are very efficient because they take a very small amount of fuel to operate. Unfortunately, this efficiency is traded for fast acceleration, so it takes a long time for ion thrusters to get going fast, but when they do they could go very far.

How it works (Diagram)

The polarities are wrong in this picture, positive is really negative, and vice versa. (sorry)

https://www.youtube.com/watch?v=TVkioe3PJz0

Something like what I'm going to do

http://makezine.com/projects/ionic-thruster/

A simple ion thruster

Ion Propulsion video on YouTube

NASA - Ion Propulsion

NASA - Ion Propulsion: ion propulsion

This Blog

This blog is for the research and planning part of building an ion thruster.
I'm going to post all my sources, write-ups and plans here.