The solar wind is a highly structured and continuously evolving plasma environment spanning a broad range of spatial and temporal scales. Large-scale features originating at the Sun evolve during heliospheric propagation, interact with the ambient plasma and with one another, and coexist with smaller-scale magneto-plasma formations generated locally. Together they create a complex hierarchy extending from streams, transients, shocks, and interaction regions to flux ropes, current sheets, discontinuities, turbulent fluctuations, waves, and kinetic-scale phenomena.
This session addresses the cross-scale evolution of this hierarchy and its role in energy transfer and dissipation throughout the heliosphere. We welcome studies of Interplanetary Coronal Mass Ejections (ICMEs) and ICME sheaths, interplanetary shocks, stream and corotating interaction regions (SIRs/CIRs), magnetic flux ropes, current sheets of different origins and scales (including the heliospheric current sheet), discontinuities, and other coherent magneto-plasma structure. Particular emphasis will be placed on how these environments generate, enhance, or modify turbulence, magnetic reconnection, plasma instabilities, and particle acceleration, and on how the resulting processes influence subsequent plasma evolution. This session is organized within the activities of the SCOSTEP Working Group under the same title.