Imaging the Solar Corona from Within: First Results from the Parker Solar Probe Telescope

Abstract

International audienceParker Solar Probe (PSP) launched in August 2018 is humanity's first probe of a stellar atmosphere. It will make measurements of the near-Sun plasma from 'within' the outer corona with gradually reduced perihelia from its first perihelia of 35 Rs in 2018-19 to 9.8 Rs in 2025. Here we report the results from the imaging observations of the electron and dust corona, whe PSP was 35-54 Rs from the solar surface, taken by the Wide-field Imager for Solar Probe (WISPR). The spacecraft was near-corotating with the solar corona throughout the observing window, which is an unprecedented situation for any type of coronal imaging. Our initial analysis uncovers a long-hypothesized depletion of the primordial dust orbiting near the Sun, reveals the plasma structure of small-scale ejections, and provides a strict test for validating model predictions of the large-scale configuration of the coronal plasma. Thus, WISPR imaging allows the study of near-Sun dust dynamics as the mission progresses. The high-resolution images of small transients, largely unresolved from 1 AU orbits, unravel the sub-structures of small magnetic flux ropes and show that the Sun continually releases helical magnetic fields in the background wind. Finally, WISPR's observations of the coronal streamer evolution confirm the large-scale topology of the solar corona but they also reveal that, as recently predicted, streamers are composed of yet smaller sub-streamers channeling continual density fluctuations at all visible scales