(Non)radial Solar Wind Propagation through the Heliosphere

Author
Keywords
Abstract
<p>The solar wind nonradial velocity components observed beyond the Alfv\ en point are usually attributed to waves, the interaction of different streams, or other transient phenomena. However, Earth-orbiting spacecraft as well as monitors at L1 indicate systematic deviations of the wind velocity from the radial direction. Since these deviations are of the order of several degrees, the calibration of the instruments is often questioned. This paper investigates for the first time the evolution of nonradial components of the solar wind flow along the path from ≍0.17 to 10 au. A comparison of observations at 1 au with those closer to or farther from the Sun based on measurements of many spacecraft at different locations in the heliosphere (Parker Solar Probe, Helios 1 and 2, Wind, Advanced Composition Explorer, Spektr-R, Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon\textquoterights Interaction with the Sun (ARTEMIS) probes, Mars Atmosphere and Volatile Evolution (MAVEN), Voyagers 1 and 2) shows that (I) the average values of nonradial components are not zero and vary in a systematic manner with the distance from the Sun and (II) their values significantly depend on the solar wind radial velocity.</p>
Year of Publication
2020
Journal
The Astrophysical Journal
Volume
897
Number
Number of Pages
L39
Date Published
07/2020
URL
https://iopscience.iop.org/article/10.3847/2041-8213/ab9ff7https://iopscience.iop.org/article/10.3847/2041-8213/ab9ff7
DOI
10.3847/2041-8213/ab9ff7