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C14/19/089#55221731

Abstract:

Observations are crucial for expanding our knowledge of solar wind physics, but their impact can be dramatically enhanced if they are complemented by theoretical and numerical modelling built on the base of the plasma conditions encountered by satellites. The aim of this work is to produce numerical support for the interpretation, but also anticipation, of in situ measurements carried out in the inner heliosphere. Our focus is on the phenomena occurring in the solar wind at kinetic scales and their influence on the macroscopic bulk parameters. This is a key aspect of the solar wind, which greatly complicates its comprehensive understanding: each of the major open questions in solar wind physics requires an insight into the interplay between the multi-scale nature of the solar wind and its observed non-equilibrium features. To accomplish our objectives, we resort to fully kinetic Particle-In-Cell (PIC) simulations. Through our simulations, and also with the support of linear theory, we produce a clear picture and a quantification of the role of processes that have a multi-scale nature and a significant impact on the dynamic and global energetics of the solar wind. Our results show the applicability and reliability of semi-implicit PIC codes in reproducing different solar wind scenarios where a coupling between physics at different spatial and temporal scales is present. Furthermore, starting from the unique and unprecedented data observed in the inner heliosphere by the Parker Solar Probe, we are able to reproduce processes that are ubiquitous in the solar wind and whose understanding can contribute to shedding light on a number of outstanding questions in plasma physics.