Alfvénic fluctuations in the expanding solar wind: Formation and radial evolution of spherical polarization

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F24%3A00584795" target="_blank" >RIV/67985815:_____/24:00584795 - isvavai.cz</a>

Výsledek na webu

<a href="https://hdl.handle.net/11104/0353355" target="_blank" >https://hdl.handle.net/11104/0353355</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1063/5.0177754" target="_blank" >10.1063/5.0177754</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Alfvénic fluctuations in the expanding solar wind: Formation and radial evolution of spherical polarization

Popis výsledku v původním jazyce

We investigate properties of large-scale solar wind Alfv & eacute,nic fluctuations and their evolution during radial expansion. We assume a strictly radial background magnetic field B parallel to R, and we use two-dimensional hybrid (fluid electrons, kinetic ions) simulations of balanced Alfv & eacute,nic 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 = |B| 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 similar to const. spatially in the plasma. We show that within the constraint of spherical polarization, variations in the radial component of the magnetic field, B-R lead to a simple relation between delta B-R and delta B = |delta B| as delta B-R similar to delta B-2/(2B), 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, delta B similar to B, this causes local magnetic field reversals, consistent with solar wind switchbacks.

Název v anglickém jazyce

Alfvénic fluctuations in the expanding solar wind: Formation and radial evolution of spherical polarization

Popis výsledku anglicky

We investigate properties of large-scale solar wind Alfv & eacute,nic fluctuations and their evolution during radial expansion. We assume a strictly radial background magnetic field B parallel to R, and we use two-dimensional hybrid (fluid electrons, kinetic ions) simulations of balanced Alfv & eacute,nic 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 = |B| 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 similar to const. spatially in the plasma. We show that within the constraint of spherical polarization, variations in the radial component of the magnetic field, B-R lead to a simple relation between delta B-R and delta B = |delta B| as delta B-R similar to delta B-2/(2B), 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, delta B similar to B, this causes local magnetic field reversals, consistent with solar wind switchbacks.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10305 - Fluids and plasma physics (including surface physics)

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Physics of Plasmas

ISSN

1070-664X

e-ISSN

1089-7674

Svazek periodika

31

Číslo periodika v rámci svazku

3

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

17

Strana od-do

032901

Kód UT WoS článku

001180029000001

EID výsledku v databázi Scopus

2-s2.0-85186959639