Polarization Ratios of Turbulent Langmuir/ -mode Waves Generated by Electron Beams in Magnetized Solar Wind Plasmas

The polarization ratios F  = ∣ E _⊥ ∣ ^2 /∣ E ∣ ^2 of beam-generated turbulent Langmuir/ ${ \mathcal Z }$ -mode ( ${ \mathcal L }{ \mathcal Z }$ ) waves and electromagnetic emissions radiated at plasma frequency ω _p from such sources are studied in weakly magnetized and randomly inhomogeneous plasm...

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Main Authors: F. J. Polanco-Rodríguez, C. Krafft, P. Savoini
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal Letters
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Online Access:https://doi.org/10.3847/2041-8213/adf4ce
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author F. J. Polanco-Rodríguez
C. Krafft
P. Savoini
author_facet F. J. Polanco-Rodríguez
C. Krafft
P. Savoini
author_sort F. J. Polanco-Rodríguez
collection DOAJ
description The polarization ratios F  = ∣ E _⊥ ∣ ^2 /∣ E ∣ ^2 of beam-generated turbulent Langmuir/ ${ \mathcal Z }$ -mode ( ${ \mathcal L }{ \mathcal Z }$ ) waves and electromagnetic emissions radiated at plasma frequency ω _p from such sources are studied in weakly magnetized and randomly inhomogeneous plasmas. Large-scale and long-term 2D/3V particle-in-cell simulations with parameters relevant to type III solar radio bursts are performed. Statistical studies using waveforms recorded by virtual satellites are carried out to determine the distributions of polarization ratios as a function of beam and plasma parameters. This efficient method, which mimics waveform recording by spacecraft in the solar wind, leads to results consistent with observations. Moreover, plasma random density fluctuations δn turn out to be the key factor responsible for the increase in polarization ratios up to F  ∼ 1. Indeed, it is demonstrated that linear mode conversion at constant frequency near ω _p of ${ \mathcal L }{ \mathcal Z }$ waves scattering on δn is the most efficient and fastest process to produce large polarization ratios in randomly inhomogeneous plasmas. This is due to electromagnetic slow extraordinary ${ \mathcal Z }$ -mode wave emission by ${ \mathcal L }{ \mathcal Z }$ wave turbulence. The results provide guidance to theoretical studies and useful support to estimate the average level of density fluctuations in solar wind plasmas.
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institution Kabale University
issn 2041-8205
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series The Astrophysical Journal Letters
spelling doaj-art-c95c4bf3a0504ac780fdb3330518581f2025-08-25T18:43:09ZengIOP PublishingThe Astrophysical Journal Letters2041-82052025-01-019892L3810.3847/2041-8213/adf4cePolarization Ratios of Turbulent Langmuir/ -mode Waves Generated by Electron Beams in Magnetized Solar Wind PlasmasF. J. Polanco-Rodríguez0https://orcid.org/0009-0005-2951-697XC. Krafft1https://orcid.org/0000-0002-8595-4772P. Savoini2https://orcid.org/0000-0002-2117-3803Laboratoire de Physique des Plasmas (LPP), CNRS, Sorbonne Université , Observatoire de Paris, Université Paris-Saclay, Ecole polytechnique, Institut Polytechnique de Paris, 91120 Palaiseau, France ; catherine.krafft@universite-paris-saclay.frLaboratoire de Physique des Plasmas (LPP), CNRS, Sorbonne Université , Observatoire de Paris, Université Paris-Saclay, Ecole polytechnique, Institut Polytechnique de Paris, 91120 Palaiseau, France ; catherine.krafft@universite-paris-saclay.fr; Institut Universitaire de France (IUF) , FranceLaboratoire de Physique des Plasmas (LPP), CNRS, Sorbonne Université , Observatoire de Paris, Université Paris-Saclay, Ecole polytechnique, Institut Polytechnique de Paris, 91120 Palaiseau, France ; catherine.krafft@universite-paris-saclay.frThe polarization ratios F  = ∣ E _⊥ ∣ ^2 /∣ E ∣ ^2 of beam-generated turbulent Langmuir/ ${ \mathcal Z }$ -mode ( ${ \mathcal L }{ \mathcal Z }$ ) waves and electromagnetic emissions radiated at plasma frequency ω _p from such sources are studied in weakly magnetized and randomly inhomogeneous plasmas. Large-scale and long-term 2D/3V particle-in-cell simulations with parameters relevant to type III solar radio bursts are performed. Statistical studies using waveforms recorded by virtual satellites are carried out to determine the distributions of polarization ratios as a function of beam and plasma parameters. This efficient method, which mimics waveform recording by spacecraft in the solar wind, leads to results consistent with observations. Moreover, plasma random density fluctuations δn turn out to be the key factor responsible for the increase in polarization ratios up to F  ∼ 1. Indeed, it is demonstrated that linear mode conversion at constant frequency near ω _p of ${ \mathcal L }{ \mathcal Z }$ waves scattering on δn is the most efficient and fastest process to produce large polarization ratios in randomly inhomogeneous plasmas. This is due to electromagnetic slow extraordinary ${ \mathcal Z }$ -mode wave emission by ${ \mathcal L }{ \mathcal Z }$ wave turbulence. The results provide guidance to theoretical studies and useful support to estimate the average level of density fluctuations in solar wind plasmas.https://doi.org/10.3847/2041-8213/adf4ceSolar windRadio burstsSolar electromagnetic emissionSolar flares
spellingShingle F. J. Polanco-Rodríguez
C. Krafft
P. Savoini
Polarization Ratios of Turbulent Langmuir/ -mode Waves Generated by Electron Beams in Magnetized Solar Wind Plasmas
The Astrophysical Journal Letters
Solar wind
Radio bursts
Solar electromagnetic emission
Solar flares
title Polarization Ratios of Turbulent Langmuir/ -mode Waves Generated by Electron Beams in Magnetized Solar Wind Plasmas
title_full Polarization Ratios of Turbulent Langmuir/ -mode Waves Generated by Electron Beams in Magnetized Solar Wind Plasmas
title_fullStr Polarization Ratios of Turbulent Langmuir/ -mode Waves Generated by Electron Beams in Magnetized Solar Wind Plasmas
title_full_unstemmed Polarization Ratios of Turbulent Langmuir/ -mode Waves Generated by Electron Beams in Magnetized Solar Wind Plasmas
title_short Polarization Ratios of Turbulent Langmuir/ -mode Waves Generated by Electron Beams in Magnetized Solar Wind Plasmas
title_sort polarization ratios of turbulent langmuir mode waves generated by electron beams in magnetized solar wind plasmas
topic Solar wind
Radio bursts
Solar electromagnetic emission
Solar flares
url https://doi.org/10.3847/2041-8213/adf4ce
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