Where and when

speaker: Daniele Telloni  
affiliation: INAF – Istituto Nazionale di Astrofisica / Osservatorio Astrofisico di Torino, Turin  
date: Thursday, May 2^nd 2024, 9am (Italian time)  
venue: Genoa (Italy), Polo Valletta Puggia – Università di Genova: DIBRIS-DIMA (room 715) and Google Meet

Turbulence: from Leonardo Da Vinci to Kolmogorov and beyond

abstract: Turbulence, or the complex and apparently disordered motion of natural fluids, is a physical phenomenon that pervades the Universe. From Leonardo da Vinci who first described its basic properties, through Richardson who gave its first phenomenological description, to Kolmogorov who provided the first theory of turbulence, tremendous advances have been made in the understanding of this fascinating phenomenon. Despite its ubiquity and progress in the field, as Nobel Laureate in physics Richard Feynman remarked, turbulence remains "the most important unsolved problem of classical physics" (Feynman et al. 1963). Indeed, turbulence is a nonlinear, non-equilibrium, and highly chaotic process, making its analytical description and predictability extremely challenging. Among the many natural frameworks in which turbulence has been observed, the solar wind holds a prominent place. The continuous stream of magnetized particles emitted by the Sun is indeed known to be in a fully developed turbulent state since the beginning of space exploration thorough robotic spacecraft, and is rightfully considered the largest turbulence laboratory. Last to be launched in 2018 and 2020, respectively, were Parker Solar Probe and Solar Orbiter. Central to these space missions, which will get closer than ever before to the Sun, carrying a full set of remote-sensing and in-situ instruments, is unveiling the origin of turbulence in the solar wind and assessing whether and to what extent it contributes to plasma heating. In this talk I will review the milestones in the investigation of turbulence, from Leonardo Da Vinci to the latest discoveries made through the joint observations by Parker Solar Probe and Solar Orbiter, which have allowed us to solve (perhaps) a 65-year-old Sun mystery by showing that turbulence dissipation is indeed the mechanism that heats and accelerates the solar wind plasma.