The way to produce these images is by keeping the objective of your camera open for long enough to gather the right amount of light. If you do it properly, you can get wonderful images of the aurora.
Cameras can be quite the beasts to deal with. One can determine the amount of light they process by many means. Imagine playing around a little restricting on what is called the ISO-number, but opening the objective for just a tad longer to compensate.
That’s just an example. I don’t really remember what I did here, apart from the fact that I did play around. Those are the colours my camera saw in nature on a rainy day.