Observations and modelling of energetic particles at interplanetary shocks with Solar Orbiter*

Interplanetary (IP) shocks are important sites of particle acceleration in the Heliosphere and can be observed in-situ utilizing spacecraft measurements. Such observations are crucial to address important aspects of energy conversion for a variety of astrophysical systems.

Under this point of view, Solar Orbiter provides observations of interplanetary shocks at different locations in the inner heliosphere with unprecedented time and energy resolution in the suprathermal (usually above 50 keV) energy range. I will present the general trends observed for such shocks, highlighting their typical parameters.

I will then focus on the theme of shock variability, examining a strong shock showing novel dispersive signals in the suprathermal particle fluxes observed by the Solar Orbiter SupraThermal Electron and Proton sensor. These are interpreted as irregular injection of particles to suprathermal energies along the shock front, as inferred using the Solar Orbiter in-situ observations and self-consistent, kinetic modelling of the shock transition propagating in pre-existing turbulence.