The Role of Alfvén Wave Dynamics on the Large-scale Properties of the Solar Wind: Comparing an MHD Simulation with Parker Solar Probe E1 Data

Victor Réville (1, 2) , Marco Velli (1) , Olga Panasenco (3) , Anna Tenerani (4) , Chen Shi (1) , Samuel T. Badman (5) , Stuart D. Bale (5, 6) , J. C. Kasper (7) , Michael L. Stevens (7) , Kelly E. Korreck (7) , J.W. Bonnell (5) , Anthony W. Case (7) , Thierry Dudok de Wit (8) , Keith Goetz , Peter R. Harvey (5) , Davin E Larson (5) , Roberto Livi (5) , David M. Malaspina (9) , Robert J. Macdowall (10) , Marc Pulupa (5) , Phyllis L Whittlesey (5)

1 EPSS - Department of Earth, Planetary and Space Sciences [Los Angeles]
2 IRAP - Institut de recherche en astrophysique et planétologie
3 Advanced Heliophysics
4 University of Texas at Austin [Austin]
5 UC Berkeley - University of California [Berkeley]
6 Imperial College London
7 Smithsonian Astrophysical Observatory
8 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
9 LASP - Laboratory for Atmospheric and Space Physics [Boulder]
10 GSFC - NASA Goddard Space Flight Center

During Parker Solar Probe's first orbit, the solar wind plasma was observed in situ closer than ever before, the perihelion on 2018 November 6 revealing a flow that is constantly permeated by large-amplitude Alfvénic fluctuations. These include radial magnetic field reversals, or switchbacks, that seem to be a persistent feature of the young solar wind. The measurements also reveal a very strong, unexpected, azimuthal velocity component. In this work, we numerically model the solar corona during this first encounter, solving the MHD equations and accounting for Alfvén wave transport and dissipation. We find that the large-scale plasma parameters are well reproduced, allowing the computation of the solar wind sources at Probe with confidence. We try to understand the dynamical nature of the solar wind to explain both the amplitude of the observed radial magnetic field and of the azimuthal velocities.

Keywords: Solar Wind; Alfvén Waves; Magnetohydrodynamics

Domains: Sciences of the Universe [physics]; Astrophysics [astro-ph]; Solar and Stellar Astrophysics [astro-ph.SR]; Physics [physics]; Physics [physics]; Space Physics [physics.space-ph]

Victor Réville, Marco Velli, Olga Panasenco, Anna Tenerani, Chen Shi, et al.. The Role of Alfvén Wave Dynamics on the Large-scale Properties of the Solar Wind: Comparing an MHD Simulation with Parker Solar Probe E1 Data. The Astrophysical Journal Supplement, 2020, Early Results from Parker Solar Probe: Ushering a New Frontier in Space Exploration, 246 (2), pp.24. ⟨10.3847/1538-4365/ab4fef⟩. ⟨insu-02941658⟩