Magnetic pole shift question
Me and my SIL were talking about scientific phenomena and I'm having trouble finding info online about a question I've always had about magnetic pole shifts. Why exactly do they occur? I'm under the impression that earth's magnetic field is a result of interactions between the flow of the molten outer core and solid inner core. Why would the outer core (with no outside intervention) suddenly change how it's flowing? I'm aware this is more a question of fluid mechanics but I feel this community would be the best equipped to atleast point me to resources for me to peruse
Edit: also it's late where I live so I'm sorry if I don't reply to the replies, I'm abit sleepy. By the time anyone gets to replying, I'm probably already gonna be conked out
Zzz