Space Balloon? Using earths electromagnetic field

I was just thinking, if you can get a balloon to 50 kilometres above the
earth, beyond 99% of the earth's atmosphere, whether you could harness the
earth's electromagnetic field to push it further into space by releasing the
balloon above the North Pole. You might be able to use ionised gas or plasma
confined by magnets, because that high up, there would be hardly any
atmosphere. My feeling is that the system would flip over and be attracted
back to earth, so maybe rotating magnets like a gyroscope would be more
stable in confining the plasma. I'm not a scientist so would appreciate your
comments.