Monday, March 01, 2021 at 12:40

https://cuboulder.zoom.us/j/96981439846

Jasper Halekas, University of Iowa

"Electron Physics in the Young Solar Wind: New Observations from the Parker Solar Probe"

Abstract:

The Parker Solar Probe (PSP) is making the first in situ measurements of the near-Sun environment at heliocentric distances closer than the ~0.29 AU previously achieved by Helios-B. I will give a brief overview of the PSP mission and its many superlatives, and will then discuss new electron observations made by PSP at heliocentric distances as close as 0.1 AU. The electrons near the Sun are similar in some ways to those observed at greater distances, with their distributions shaped by a combination of macroscopic influences and by both collisional and collisionless kinetic processes. However, we observe several new trends apparently unique to the near-Sun environment, including anticorrelations between the solar wind flow speed and both the electron temperature and heat flux. The electron temperature-flow speed anticorrelation appears to reveal the imprint of the initial conditions at the wind's source in the corona, while the electron heat flux-flow speed anticorrelation likely results from the operation of collisionless heat flux regulation mechanisms. The mechanisms that shape the electron distributions near the Sun have implications for heat conduction in stellar winds and potentially in other astrophysical contexts.

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