In this section
@article{Matteini:2024:10.1063/5.0177754,
author = {Matteini, L and Tenerani, A and Landi, S and Verdini, A and Velli, M and Hellinger, P and Franci, L and Horbury, TS and Papini, E and Stawarz, JE},
doi = {10.1063/5.0177754},
journal = {Physics of Plasmas},
title = {Alfvénic fluctuations in the expanding solar wind: formation and radial evolution of spherical polarization},
url = {http://dx.doi.org/10.1063/5.0177754},
volume = {31},
year = {2024}
}
TY - JOUR
AB - We investigate properties of large-scale solar wind Alfvénic fluctuations and their evolution during radial expansion. We assume a strictly radial background magnetic field B k R, and we use two-dimensional hybrid (fluid electrons, kinetic ions) simulations of balanced Alfvénic turbulence in the plane orthogonal to B; the simulated plasma evolves in a system comoving with the solar wind (i.e., in the expanding box approximation). Despite some model limitations, simulations exhibit important properties observed in the solar wind plasma: Magnetic field fluctuations evolve toward a state with low-amplitude variations in the amplitude B ¼ jBj and tend to a spherical polarization. This is achieved in the plasma by spontaneously generating field aligned, radial fluctuations that suppress local variations of B, maintaining B const. spatially in the plasma. We show that within the constraint of spherical polarization, variations in the radial component of the magnetic field, BR lead to a simple relation between dBR and dB ¼ jdBj as dBR dB2=ð2BÞ, which correctly describes the observed evolution of the rms of radial fluctuations in the solar wind. During expansion, the background magnetic field amplitude decreases faster than that of fluctuations so that their the relative amplitude increases. In the regime of strong fluctuations, dB B, this causes local magnetic field reversals, consistent with solar wind switchbacks.
AU - Matteini,L
AU - Tenerani,A
AU - Landi,S
AU - Verdini,A
AU - Velli,M
AU - Hellinger,P
AU - Franci,L
AU - Horbury,TS
AU - Papini,E
AU - Stawarz,JE
DO - 10.1063/5.0177754
PY - 2024///
SN - 1070-664X
TI - Alfvénic fluctuations in the expanding solar wind: formation and radial evolution of spherical polarization
T2 - Physics of Plasmas
UR - http://dx.doi.org/10.1063/5.0177754
UR - https://pubs.aip.org/aip/pop/article/31/3/032901/3268444/Alfvenic-fluctuations-in-the-expanding-solar-wind
VL - 31
ER -