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Session: Heliophysics and the Solar System

Name: Prof. Kanaris Tsinganos (National & Kapodistrian Univ. of Athens)
Coauthors: No coauthors were included.
Type: Oral
Title: Title of invited talk: Latest developments in understanding our Sun via recent space probes, in conjuction with the pioneering discoveries of the founder of Solar & Space Physics Eugene Parker
Abstract:

The latest developments and current understanding of our life-giver Sun, the Lydian stone (Λυδία λίθος) of astrophysics and the shaper of Space Weather will be discussed. First, the emergence of the Solar Wind (SW) will be presented, from his cradle in the lowest parts of the superhot solar atmosphere, to its termination at the Heliopause, dramatically affecting in between the terrestrial environment and the entire planetary system. Although the importance of the discovery of the SW for Heliophysics is equivalent to Kepler laws for planetary motion (in a vacuo systema planetarium) and Newton’s laws of motion and universal gravitation which explained them, the original SW paper by Parker, when submitted to the Astrophysical Journal (ApJ), was rejected by two eminent referees. This interesting historical fact will also be noted in the talk, via Parker’s and Chandrasekhar’s (ApJ editor) personal narratives to the speaker. Extension of the universal SW idea to General Relativity and the recent observation of the shadow of the black hole at the centre of the galaxy Messier 87 (M87) together with the powerful jet expelled from the disk around the M87 supermassive black hole, in conjuction with our theoretical predictions, will be also shortly discussed. Next, we shall follow the various solar fireworks and the corresponding plasma physics and magnetohydrodynamics through the pioneering studies and discoveries handed down to us by the greatest Heliospheric and Space physicist of our century, Eugene Parker (1927 – 2022). Finally, some recent findings by the Solar Orbiter and Parker Solar probe spacecrafts orbiting the Sun will be presented, including that of more than 1500 small, flickering coronal brightenings nicknamed “campfires”. These nanoflares, which had not been observed before, seem to represent a previously unseen fine structure of the region where the coronal heating mystery is suspected to be rooted. They can be theoretically understood as the basic inescapable result of the nonequilibrium of nonsymmetric topologies of magnetic fields in the restless and superhot magnetohydrodynamic solar atmosphere.