In-situ Switchback Formation in the Expanding Solar Wind

Author
Keywords
Abstract
<p>Recent near-Sun solar-wind observations from Parker Solar Probe have found a highly dynamic magnetic environment, permeated by abrupt radial-field reversals, or "switchbacks." We show that many features of the observed turbulence are reproduced by a spectrum of Alfv\ enic fluctuations advected by a radially expanding flow. Starting from simple superpositions of low-amplitude outward-propagating waves, our expanding-box compressible magnetohydrodynamic simulations naturally develop switchbacks because (i) the normalized amplitude of waves grows due to expansion and (ii) fluctuations evolve toward spherical polarization (i.e., nearly constant field strength). These results suggest that switchbacks form in situ in the expanding solar wind and are not indicative of impulsive processes in the chromosphere or corona.</p>
Year of Publication
2020
Journal
The Astrophysical Journal
Volume
891
Number
Number of Pages
L2
Date Published
03/2020
URL
https://iopscience.iop.org/article/10.3847/2041-8213/ab74e1
DOI
10.3847/2041-8213/ab74e1