The physical processes that produce the solar wind and the rich set of phenomena associated with solar activity are still highly debated and their understanding is a prime research goal in heliophysics. The latter is at the dawn of a golden age with the imminent launch of the Solar Orbiter, Parker Solar Probe and PROBA-3 missions, that will provide radically new observations of the Sun's atmosphere. Though each mission has its own specific scientific goals and promises great advances in our understanding of the Sun and the interplanetary medium, taken together the three missions will provide the first contemporaneuos genuinally 3D exploration of the Heliosphere. To make full use of the data provided by these missions it is paramount to develop improved numerical models and new tools enabling further tests of the various theories proposed to explain the processes driving the dynamic corona. This session focuses on the opportunities brought by these new missions individually and by the possible synergies between the highly complementary instrumentation in space and on the ground made available by the heliophysics observatory as a whole. We also solicit contributions that present recent model and tool developments useful to accomplish such coordinated studies and/or that point to currently missing assets that should ideally be developed before missions are in operation.

Wave-particle interactions represent a unique mechanism of an energy transfer in the nearly collisionless plasma environment of the Earth's magnetosphere, affecting ultimately distribution functions of energetic particles trapped in the Van Allen radiation belts. Their evaluation, along with the quantification of the resulting particle acceleration, transport, and loss, is thus crucial for understanding the dynamics of the radiation belts. The aim of this session is the dynamics of energetic particle populations in the Earth's magnetosphere, as well as generation mechanisms and properties of involved electromagnetic emissions (EMIC, chorus, hiss, fast magnetosonic waves, etc.) in various frequency ranges (ULF, ELF, VLF). Theoretical and model contributions, as well as observational studies using data from recent satellite missions (ERG-Arase, Cluster, MMS, THEMIS, Van Allen Probes, etc.) and ground-based instruments are encouraged.

This joint session invites papers that are related to the mesosphere and lower thermosphere. It addresses the topical fields of the VarSITI (Variability of the Sun and Its Terrestrial Impact) program initiated by SCOSTEP, focusing on the role of the sun and the middle atmosphere/thermosphere/ionosphere in climate (ROSMIC). Contributions studying radiation, chemistry, energy balance, atmospheric tides, planetary waves, gravity waves, neutral-ion coupling, and the interaction of the various processes involved are welcome. This includes work on model data as well as measurements from satellites and ground based platforms such as ALOMAR.

The Sun experienced a period of very, perhaps exceptionally high activity during the 20th century, now called the Grand Modern Maximum (GMM). However, the relative height of the GMM with respect to the solar activity maxima in the previous centuries still remains under debate. Little is known yet about the causes of long-term solar activity variability in general, or on the detailed processes related to the evolution of solar magnetic fields during the GMM. However, it is known that the GMM has dramatically affected the condtions in the heliosphere, including the Earth.

This session gives a framework for studies on the many aspects of long-term solar activity (sunspots, TSI/SSI, coronal holes etc), especially to those related to the GMM, the different changes and phenomena taking place in the Sun over the GMM period, as well as their consequences in the heliosphere and in the near-Earth space. Effects of this variability to the Earth's atmosphere and climate are also welcome, as well as studies of other grand maxima and minima, and considerations about the future of the solar-terrestrial environment after the GMM.