Proton Beam Development in the Expanding Solar Wind

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F19%3A10406372" target="_blank" >RIV/00216208:11320/19:10406372 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.mff.cuni.cz/veda/konference/wds/proc/pdf19/WDS19_23_f2_Durovcova.pdf" target="_blank" >https://www.mff.cuni.cz/veda/konference/wds/proc/pdf19/WDS19_23_f2_Durovcova.pdf</a>

DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Proton Beam Development in the Expanding Solar Wind

Popis výsledku v původním jazyce

In the multi-component, turbulent and weakly collisional solar wind, kinetic processes predominate and significant deviations from a local thermodynamic equilibrium may arise. Non-thermal features such as a second population of any ion component (ion beam) are often observed. However, the underlying processes which drive development of such features are still not fully explained. We focus on properties of the proton beam, the secondary proton component generally flowing faster than the proton core by about local Alfv&apos;en speed. With motivation to study proton beam development during solar wind expansion, we reprocessed 3D ion VDFs measured by the Helios spacecraft between 0.28 AU and 1 AU from the Sun. We found that the relative content of the proton beam to proton core in the fast solar wind increases with increasing distance from the Sun. On the other hand, it almost does not change in the slow solar wind. To explain these observations, we studied the proton beam properties for various solar wind conditions. We found that the proton beam and α particle contents are coupled together. Moreover, we showed that a behavior of the proton beam in the high-speed streams corresponds well to the model based on interaction between protons and oblique Alfven wave. In the slow solar wind, the proton beam could be formed by the parametric instability.

Název v anglickém jazyce

Proton Beam Development in the Expanding Solar Wind

Popis výsledku anglicky

In the multi-component, turbulent and weakly collisional solar wind, kinetic processes predominate and significant deviations from a local thermodynamic equilibrium may arise. Non-thermal features such as a second population of any ion component (ion beam) are often observed. However, the underlying processes which drive development of such features are still not fully explained. We focus on properties of the proton beam, the secondary proton component generally flowing faster than the proton core by about local Alfv&apos;en speed. With motivation to study proton beam development during solar wind expansion, we reprocessed 3D ion VDFs measured by the Helios spacecraft between 0.28 AU and 1 AU from the Sun. We found that the relative content of the proton beam to proton core in the fast solar wind increases with increasing distance from the Sun. On the other hand, it almost does not change in the slow solar wind. To explain these observations, we studied the proton beam properties for various solar wind conditions. We found that the proton beam and α particle contents are coupled together. Moreover, we showed that a behavior of the proton beam in the high-speed streams corresponds well to the model based on interaction between protons and oblique Alfven wave. In the slow solar wind, the proton beam could be formed by the parametric instability.

Druh

D - Stať ve sborníku

CEP obor

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OECD FORD obor

10305 - Fluids and plasma physics (including surface physics)

Projekt

<a href="/cs/project/GA19-18993S" target="_blank" >GA19-18993S: Přenos energie variací slunečního větru z velkých do malých škál</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2019

Kód důvěrnosti údajů

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

Název statě ve sborníku

WDS&apos;19 Proceedings of Contributed Papers — Physics

ISBN

978-80-7378-409-6

ISSN

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e-ISSN

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Počet stran výsledku

7

Strana od-do

131-137

Název nakladatele

Matfyzpress

Místo vydání

Praha

Místo konání akce

Praha

Datum konání akce

4. 6. 2019

Typ akce podle státní příslušnosti

EUR - Evropská akce

Kód UT WoS článku

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