The basic paradigm for magnetospheric dynamics was laid out in the early part of the space age by Dungey. However, it has taken over 40 years for us to fully appreciate the dynamical nature of the magnetosphere and the controlling parameters. We now enter a period when quantitative measurements of the physical processes can be made. In this seminar I will review the current state of our knowledge, concentrating on how ground based radars, such as those that form the Super Dual Auroral Radar Network (SuperDARN) have played a key role in recent developments which have changed our view on the magnetosphere as a dynamic system. Importantly, bringing together data ground based and satellite instruments have proven to be critical in these new developments. I will also demonstrate how the observations made at earth can be used in other astrophysical plasmas. Finally, I will look at the outstanding questions and how these may be addressed in the next decade.