Mesoscale Solar Wind Structures: Their Creation and Magnetospheric Impact

Mesoscale structure in the solar wind (~tens to several thousands of Mm) are created in two possible ways: those that come directly from the Sun, and those formed through processing en route as the solar wind advects outward. Complexity arises from a competition between the imposed and injected structures that survive from the Sun and turbulence and other dynamical evolution. Understanding the source and evolution of solar wind mesoscale structures is important because it constrains the physics of turbulent processes, and it contains information on how the Sun forms the solar wind. We demonstrate that mesoscale structures that are a part of solar wind formation leave imprints of coronal heating, the energization in the extended corona, and how mass is released into the solar wind. We describe how understanding the 3D, time-dependent connectivity from the low solar atmosphere through the upper corona is a crucial for understanding mesoscale structure formation, and describe how current and upcoming missions are making progress on this understanding. We argue that the next era of scientific progress requires connecting the microphysics to the mesoscale physics, as well as system science that connects layers of the sun out into the heliosphere. Lastly, we describe the ways in which mesoscale solar wind structures comprise the ground state of space weather, as they are continually buffeting planetary magnetospheres.