MPS Seminar: Multi spacecraft observations of the Sun’s variability, from its atmosphere to planetary environments. (M. Janvier)

The Sun’s variability expresses itself in various ways, from its eleven-year cycle, to its large-scale magnetic field permeating the solar system, to space weather impact via short time scale events such as solar flares, coronal mass ejections, and energetic particles. The latter are among the most energetic events in our solar system. Accompanied by intense UV emissions and even X-rays, clouds of magnetized plasma injected into the heliosphere can interact with planetary environments, with noticeable impacts on human societies.

The improvement in our observation capabilities of the Sun has provided a good number of observables, which in turn have made it possible to build models of solar flares and their accompanying particle and magnetic storms. In the recent years, access to multi point observations with missions close to the Sun, such as Parker Solar Probe and Solar Orbiter, have provided new constraints, for example in the extension of models of solar eruptions in 3D, which we will present here.

Augmented by other space missions and ground-based telescopes such DKIST and solar telescopes in the Canary Islands, new dataset have also opened a door to analysing the multi-layer Sun and its longer temporal variability, for example the emergence, evolution and the decay phase of long-lived active regions.

Finally, we will see how planetary missions on their way to their targets or at their targets, such as Bepi Colombo and JUICE and Mars missions, can fill some gap in understanding the spatial extension of the solar variability, for example by measuring energetic space weather events in their science and housekeeping data.