Recently I found this video of a 500 kilovolts line being opened under load.
When the switch contacts are pulled apart an electric arc predictably starts. While the contacts are close to each other the arc runs along a straight path between the contacts. Then as contacts are pulled further apart the arc starts to bend and turn into a steep curve and its length becomes several times greater than the distance between the contacts. Then finally the arc just fades out.
That doesn't make sense to me. As I see it the arc should take the least resistance path and that's clearly a straight path, not a steep curve. Even more, if the arc takes a curved path why would it fade out suddenly instead of just taking a less curved path of less resistance and continue running?
Why does the arc behave this way - first prefers a curved path and then suddenly fades out?