re: Quibble on diagram used in video.
Yep, and Themis hasn't done too bad at explaining some things.
[One wonders if there are double layers in the magntotail that are storing energy and then releasing it when they break down?]
Interesting. I understand and it does make sense, but the question is 'how?'.
[Much of the stuff, as you say, it probably in space. However, currents in space can induce currents on/in the ground as well.]
Yes, but to both of those of course it would have a great deal to do with our/Earth's magnetosphere which still holds mysteries of it's own.
The more we know, the more we tend to ask.