Generation of suprathermal electrons by collective processes in collisional plasma
Autor(a) principal: | |
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Data de Publicação: | 2017 |
Outros Autores: | , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFRGS |
Texto Completo: | http://hdl.handle.net/10183/173037 |
Resumo: | The ubiquity of high-energy tails in the charged particle velocity distribution functions (VDFs) observed in space plasmas suggests the existence of an underlying process responsible for taking a fraction of the charged particle population out of thermal equilibrium and redistributing it to suprathermal velocity and energy ranges. The present Letter focuses on a new and fundamental physical explanation for the origin of suprathermal electron velocity distribution function (EVDF) in a collisional plasma. This process involves a newly discovered electrostatic bremsstrahlung (EB) emission that is effective in a plasma in which binary collisions are present. The steady-state EVDF dictated by such a process corresponds to a Maxwellian core plus a quasi-inverse power-law tail, which is a feature commonly observed in many space plasma environments. In order to demonstrate this, the system of selfconsistent particle- and wave-kinetic equations are numerically solved with an initially Maxwellian EVDF and Langmuir wave spectral intensity, which is a state that does not reflect the presence of EB process, and hence not in force balance. The EB term subsequently drives the system to a new force-balanced steady state. After a long integration period it is demonstrated that the initial Langmuir fluctuation spectrum is modified, which in turn distorts the initial Maxwellian EVDF into a VDF that resembles the said core-suprathermal VDF. Such a mechanism may thus be operative at the coronal source region, which is characterized by high collisionality. |
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Ferrão, Sabrina TigikZiebell, Luiz FernandoYoon, Peter H.2018-02-28T02:27:57Z20170004-637Xhttp://hdl.handle.net/10183/173037001055818The ubiquity of high-energy tails in the charged particle velocity distribution functions (VDFs) observed in space plasmas suggests the existence of an underlying process responsible for taking a fraction of the charged particle population out of thermal equilibrium and redistributing it to suprathermal velocity and energy ranges. The present Letter focuses on a new and fundamental physical explanation for the origin of suprathermal electron velocity distribution function (EVDF) in a collisional plasma. This process involves a newly discovered electrostatic bremsstrahlung (EB) emission that is effective in a plasma in which binary collisions are present. The steady-state EVDF dictated by such a process corresponds to a Maxwellian core plus a quasi-inverse power-law tail, which is a feature commonly observed in many space plasma environments. In order to demonstrate this, the system of selfconsistent particle- and wave-kinetic equations are numerically solved with an initially Maxwellian EVDF and Langmuir wave spectral intensity, which is a state that does not reflect the presence of EB process, and hence not in force balance. The EB term subsequently drives the system to a new force-balanced steady state. After a long integration period it is demonstrated that the initial Langmuir fluctuation spectrum is modified, which in turn distorts the initial Maxwellian EVDF into a VDF that resembles the said core-suprathermal VDF. Such a mechanism may thus be operative at the coronal source region, which is characterized by high collisionality.application/pdfengThe astrophysical journal. Bristol. Vol. 849, no. 2 ( 2017), L30, 5 p.Vento solarProcessos de colisao em plasmasOndas de Langmuir em plasmasSolar windSun: coronaSun: particle emissionGeneration of suprathermal electrons by collective processes in collisional plasmaEstrangeiroinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFRGSinstname:Universidade Federal do Rio Grande do Sul (UFRGS)instacron:UFRGSORIGINAL001055818.pdf001055818.pdfTexto completo (inglês)application/pdf296497http://www.lume.ufrgs.br/bitstream/10183/173037/1/001055818.pdf593dd258f62268c255cbc8f0d5ca50f0MD51TEXT001055818.pdf.txt001055818.pdf.txtExtracted Texttext/plain28367http://www.lume.ufrgs.br/bitstream/10183/173037/2/001055818.pdf.txt1d7bc86f44f511f5684859740a50a3c0MD52THUMBNAIL001055818.pdf.jpg001055818.pdf.jpgGenerated Thumbnailimage/jpeg2104http://www.lume.ufrgs.br/bitstream/10183/173037/3/001055818.pdf.jpg36d82e6860091741e5b7bfd12a27b7beMD5310183/1730372023-09-24 03:37:35.471835oai:www.lume.ufrgs.br:10183/173037Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2023-09-24T06:37:35Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false |
dc.title.pt_BR.fl_str_mv |
Generation of suprathermal electrons by collective processes in collisional plasma |
title |
Generation of suprathermal electrons by collective processes in collisional plasma |
spellingShingle |
Generation of suprathermal electrons by collective processes in collisional plasma Ferrão, Sabrina Tigik Vento solar Processos de colisao em plasmas Ondas de Langmuir em plasmas Solar wind Sun: corona Sun: particle emission |
title_short |
Generation of suprathermal electrons by collective processes in collisional plasma |
title_full |
Generation of suprathermal electrons by collective processes in collisional plasma |
title_fullStr |
Generation of suprathermal electrons by collective processes in collisional plasma |
title_full_unstemmed |
Generation of suprathermal electrons by collective processes in collisional plasma |
title_sort |
Generation of suprathermal electrons by collective processes in collisional plasma |
author |
Ferrão, Sabrina Tigik |
author_facet |
Ferrão, Sabrina Tigik Ziebell, Luiz Fernando Yoon, Peter H. |
author_role |
author |
author2 |
Ziebell, Luiz Fernando Yoon, Peter H. |
author2_role |
author author |
dc.contributor.author.fl_str_mv |
Ferrão, Sabrina Tigik Ziebell, Luiz Fernando Yoon, Peter H. |
dc.subject.por.fl_str_mv |
Vento solar Processos de colisao em plasmas Ondas de Langmuir em plasmas |
topic |
Vento solar Processos de colisao em plasmas Ondas de Langmuir em plasmas Solar wind Sun: corona Sun: particle emission |
dc.subject.eng.fl_str_mv |
Solar wind Sun: corona Sun: particle emission |
description |
The ubiquity of high-energy tails in the charged particle velocity distribution functions (VDFs) observed in space plasmas suggests the existence of an underlying process responsible for taking a fraction of the charged particle population out of thermal equilibrium and redistributing it to suprathermal velocity and energy ranges. The present Letter focuses on a new and fundamental physical explanation for the origin of suprathermal electron velocity distribution function (EVDF) in a collisional plasma. This process involves a newly discovered electrostatic bremsstrahlung (EB) emission that is effective in a plasma in which binary collisions are present. The steady-state EVDF dictated by such a process corresponds to a Maxwellian core plus a quasi-inverse power-law tail, which is a feature commonly observed in many space plasma environments. In order to demonstrate this, the system of selfconsistent particle- and wave-kinetic equations are numerically solved with an initially Maxwellian EVDF and Langmuir wave spectral intensity, which is a state that does not reflect the presence of EB process, and hence not in force balance. The EB term subsequently drives the system to a new force-balanced steady state. After a long integration period it is demonstrated that the initial Langmuir fluctuation spectrum is modified, which in turn distorts the initial Maxwellian EVDF into a VDF that resembles the said core-suprathermal VDF. Such a mechanism may thus be operative at the coronal source region, which is characterized by high collisionality. |
publishDate |
2017 |
dc.date.issued.fl_str_mv |
2017 |
dc.date.accessioned.fl_str_mv |
2018-02-28T02:27:57Z |
dc.type.driver.fl_str_mv |
Estrangeiro info:eu-repo/semantics/article |
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http://hdl.handle.net/10183/173037 |
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0004-637X |
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001055818 |
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http://hdl.handle.net/10183/173037 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.ispartof.pt_BR.fl_str_mv |
The astrophysical journal. Bristol. Vol. 849, no. 2 ( 2017), L30, 5 p. |
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info:eu-repo/semantics/openAccess |
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openAccess |
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