models of solar wind ions and elections and their interaction with plasma waves, but also direction comparison of the data with kinetic model results will be possible. Additionally, because together Solar Orbiter and the Parker Solar Probe will cover such a wide range of solar distances, it will be possible to study (a) the radial evolution of plasma turbulence in the expanding solar wind, (b) temperature anisotropy evolution for different particle species, and (c) to distinguish whether power‐law suprathermal tails are formed due to local turbulent processes in the solar wind or have their origin in the solar corona. Similarly, we will be able to investigate the nature of the formation of in situ mesoscale structures, weighing the importance of turbulent processing or magnetic reconnection that occurs during transit against time‐dynamic magnetic reconnection in the corona or stationary coronal streamer substructure.
Despite the many unanswered questions surrounding the formation and propagation of the solar wind, it is obvious that heliophysics is poised on the threshold of an exciting era of discovery.
ACKNOWLEDGMENTS
OA is supported by the French Centre National d’Etude Spatiales (CNES). VP and CV thank ISSI for the project on kappa distributions. APR, YU, BL, RP, and ML acknowledge support from the French space agency (Centre National des Etudes Spatiales; CNES; https://cnes.fr/fr) that funds activity in plasma physics data center (Centre de Données de la Physique des Plasmas; CDPP; http://cdpp.eu/) and the Multi Experiment Data & Operation Center (MEDOC; https://idoc.ias.u‐psud.fr/MEDOC), and the space weather team in Toulouse (Solar‐Terrestrial Observations and Modelling Service; STORMS; http://storms‐service.irap.omp.eu/). This includes funding for the data mining tools AMDA (http://amda.cdpp.eu/), CLWEB (clweb.cesr.fr/), and the propagation tool (http://propagationtool.cdpp.eu). APR, YW, BL, RP, and ML also acknowledge financial support from ERC for the project SLOW_SOURCE ‐ DLV‐819189 as well as ANR project COROSHOCK No ANR − 18 − ERC1 − 0006 − 01.
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