Large-scale, or globally coherent modulations of magnetic field and plasma on minutes to hours timescales are a common feature of the magnetosphere. Common drivers include the dynamic effects of solar wind CME/shock impacts and mesoscale density structures remnant from solar coronal processes. These external drivers squeeze the magnetosphere like a sponge, resulting in enhanced radiation belt electron loss due to loss cone modulation, enhanced outer boundary loss, or via atmospheric scattering by compression-generated plasma waves. This global response is not currently well understood but may be a critical component of solar wind-magnetosphere-ionosphere coupling. This session solicits observations from satellites, balloons, and ground-based observatories of the nature and origin of external drivers, and subsequent magnetospheric particle/wave dynamics and resulting loss. We also welcome initial modeling efforts into these phenomena.