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The Electron Temperature and Anisotropy in the Solar Wind. Comparison of the Core and Halo Populations

SYSNO ASEP	0463539
Document Type	J - Journal Article
R&D Document Type	Journal Article
Subsidiary J	Článek ve WOS
Title	The Electron Temperature and Anisotropy in the Solar Wind. Comparison of the Core and Halo Populations
Author(s)	Pierrard, V. (BE) Lazar, M. (BE) Poedts, S. (BE) Štverák, Štěpán (ASU-R)_{RID, ORCID} Maksimovic, M. (FR) Trávníček, Pavel M. (ASU-R)_{RID, ORCID}
Source Title	Solar Physics. - : Springer - ISSN 0038-0938 Roč. 291, č. 7 (2016), s. 2165-2179
Number of pages	15 s.
Publication form	Print - P
Language	eng - English
Country	NL - Netherlands
Keywords	solar wind ; electron velocity distributions ; temperature anisotropy
Subject RIV	BN - Astronomy, Celestial Mechanics, Astrophysics
R&D Projects	GA15-17490S GA ČR - Czech Science Foundation (CSF)
Institutional support	ASU-R - RVO:67985815
UT WOS	000382094000014
EID SCOPUS	84982840942
DOI	10.1007/s11207-016-0961-7
Annotation	This article presents a detailed observational analysis of these two components, providing estimations of their temperatures and temperature anisotropies, and decoding any potential interdependence that their properties may indicate. The dataset used in this study includes more than 120 000 of the distributions measured by three missions in the ecliptic within an extended range of heliocentric distances from 0.3 to over 4 AU. The core temperature is found to decrease with the radial distance, while the halo temperature slightly increases, clarifying an apparent contradiction in previous observational analyses and providing valuable clues about the temperature of the kappa-distributed populations. For low values of the power-index kappa, these two components manifest a clear tendency to deviate from isotropy in the same direction, which seems to confirm the existence of mechanisms with similar effects on both components, e.g., the solar wind expansion, or the particle heating by the fluctuations. However, the existence of plasma states with anticorrelated anisotropies of the core and halo populations and the increase in their number for high values of the power-index kappa suggest a dynamic interplay of these components, mediated, most probably, by the anisotropy-driven instabilities.
Workplace	Astronomical Institute
Contact	Radka Svašková, bibl@asu.cas.cz, Tel.: 323 620 326
Year of Publishing	2017

Number of the records: 1