There are significant differences between the magnetospheres of Jupiter, Saturn, Uranus, and Neptune. Studying these diverse systems is important for our understanding of the interaction between the Sun and a magnetized planet, and is relevant to the study of exoplanetary magnetospheres. In this session we invite submissions covering the configuration and dynamics of plasma and magnetic fields in the giant planet magnetospheres. The magnetospheric dynamics topics covered include solar wind-magnetosphere interactions, transport of magnetospheric plasma, magnetotail processes, and periodicities. We particularly encourage submissions that compare giant planet magnetospheres, or compare the magnetospheres of giant planets to those of terrestrial planets. The session will be an ideal forum for the discussion of recent advances in our understanding of these systems, and will be relevant to planned future missions to these planets. A special attention will be given to recent modeling effort on the plasma, dust and radiation environments at giant planets and their moons in relation to new missions under definition.