Whistler Waves and Electron Properties in the Inner Heliosphere: Helios Observations

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378289%3A_____%2F20%3A00535838" target="_blank" >RIV/68378289:_____/20:00535838 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.3847/1538-4357/ab94a1" target="_blank" >https://doi.org/10.3847/1538-4357/ab94a1</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3847/1538-4357/ab94a1" target="_blank" >10.3847/1538-4357/ab94a1</a>

Result language

angličtina

Original language name

Whistler Waves and Electron Properties in the Inner Heliosphere: Helios Observations

Original language description

We present the analysis of narrowband whistler wave signatures observed in the inner heliosphere (0.3-1 au). These signatures are bumps in the spectral density in the 10-200 Hz frequency range of the AC magnetic field as measured by the search coil magnetometer on board the Helios 1 spacecraft. We show that the majority of whistler signatures are observed in the slow solar wind (<500 km s(-1)) and their occurrence increases with the radial distance (R), from similar to 3% at 0.3 au to similar to 10% at 0.9 au. In the fast solar wind (>600 km s(-1)), whistler activity is significantly lower: whistler signatures start to appear forR > 0.6 au and their number increases from similar to 0.03% at 0.65 au to similar to 1% at 0.9 au. We have studied the variation of the electron core and halo anisotropy (T-e/T-e parallel to), as well as the electron normalized heat flux as a function ofRand of the solar wind speed. We find that, in the slow wind electron core and halo anisotropy is higher than in fast one, and also that these anisotropies increase radially in both types of winds, which is in line with the occurrence of whistler signatures. We hypothesize the existence of a feedback mechanism to explain the observed radial variations of the occurrence of whistlers in relation with the halo anisotropy.

Czech name

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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

—

OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2020

Confidentiality

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

Name of the periodical

Astrophysical Journal

ISSN

0004-637X

e-ISSN

—

Volume of the periodical

897

Issue of the periodical within the volume

2

Country of publishing house

US - UNITED STATES

Number of pages

15

Pages from-to

118

UT code for WoS article

000551649000001

EID of the result in the Scopus database

2-s2.0-85088592108