Evolution of Relative Drifts in the Expanding Solar Wind: Helios Observations

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F19%3A10395973" target="_blank" >RIV/00216208:11320/19:10395973 - isvavai.cz</a>

Result on the web

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=uItHiXFiV" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=uItHiXFiV</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/s11207-019-1490-y" target="_blank" >10.1007/s11207-019-1490-y</a>

Result language

angličtina

Original language name

Evolution of Relative Drifts in the Expanding Solar Wind: Helios Observations

Original language description

Ion velocity distribution functions (VDFs) measured in-situ in the solar wind show often large deviations from asimple Maxwellian distribution. Even amain part of the proton VDF (proton core) situated around the global maximum maintains abi-Maxwellian character. Moreover, skewness, related to a non-thermal tail or proton beam, is often observed. In addition to these two proton populations, various heavy ion species are present and their VDFs also exhibit the mentioned non-thermal features. In the proton core frame, minor components including ion beams drift along the interplanetary magnetic field and their average differential velocities decrease with an increasing distance from the Sun. We present reprocessing of the VDFs measured by the Helios spacecraft with a motivation to discuss evolutions of relative drifts between three dominant components - the proton core, proton beam, and alpha-particle core at different distances from the Sun. Our processing is based on assumptions that partial VDFs of all these components can be approximated by abi-Maxwellian distribution. We compare results of this novel procedure with those from previous computation results and introduce basic characteristics of the VDF components in both slow and fast solar wind streams. Finally, we investigate the correlated variations of the velocity ratios on the ion components and magnetic field orientations occurring independently on the radial distance from the Sun.

Czech name

—

Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10305 - Fluids and plasma physics (including surface physics)

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

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

Publication year

2019

Confidentiality

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

Name of the periodical

Solar Physics

ISSN

0038-0938

e-ISSN

—

Volume of the periodical

294

Issue of the periodical within the volume

7

Country of publishing house

NL - THE KINGDOM OF THE NETHERLANDS

Number of pages

15

Pages from-to

97

UT code for WoS article

000477049900002

EID of the result in the Scopus database

2-s2.0-85069439279