Field-aligned currents (FACs) play many roles in the Earth's and other planets' magnetospheres. An important consequence of FACs is the aurora but this is not the only one. FACs are known to be part of the substorm current wedge, but the FAC structure within the wedge does not appear to be as simple as has been thought. Occurring in different regions of the magnetosphere, FACs have also been associated with different plasma structures such as bursty bulk flows, travelling convection vortices, nightside flux transfer events, etc. The reconnection region is also a generator of field-aligned currents and their consequences for magnetospheric and auroral processes are being investigated. FACs play a significant role in Alfven waves, the only MHD wave that carries such currents. Moreover, FACs can be found in large-scale and small-scale structures which affect the dynamics of the magnetosphere on different scales. These few examples of phenomena that are associated with FACs illustrate their significance and ubiquity. Hence, an understanding of the processes which generate FACs is necessary if we want to understand the individual phenomena as well as the magnetosphere as a whole. The motion of FACs through the magnetosphere is also an intriguing problem. The presence of multiple spacecraft has given us the necessary tool to make progress in this area.

This session solicits contributions (data analysis, theory and simulation) on new results on FACs, in particular: (1) the mechanisms generating FACs, (2) their properties (both small-scale and large-scale), (3) their development and propagation through the magnetosphere, and (4) the relationship of FACs to magnetospheric dynamics.