Characteristics of Solar Wind Fluctuations at and below Ion Scales

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F19%3A10395971" target="_blank" >RIV/00216208:11320/19:10395971 - isvavai.cz</a>

Výsledek na webu

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

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3847/1538-4357/ab22b8" target="_blank" >10.3847/1538-4357/ab22b8</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Characteristics of Solar Wind Fluctuations at and below Ion Scales

Popis výsledku v původním jazyce

Kinetic-scale fluctuations in magnetized collisionless plasmas, such as a solar wind, attract attention owing to their vital role in the dynamics of the dissipation of free energy to random particle motion. As the free energy cascades in the inertial range of turbulence, fluctuations at ion characteristic scales become more compressible. Measurements show that these fluctuations possess highly oblique propagation angles with respect to the background magnetic field and follow theoretical predictions for kinetic Alfven waves (KAWs). We performed a. large (465 cases) statistical study of normalized fluctuations of the density, bulk velocity, and magnetic field around ion gyroscale and concentrated on (i) their compressibility, (ii) the ratio of density and magnetic field fluctuations, and (iii) the ratio of density and velocity fluctuations. We find that observed fluctuations follow the two-fluid prediction for KAWs generally, but the spread of measured values around their theoretical predictions is large. The analysis of measurement uncertainties shows that the difference between the observed and predicted levels of fluctuations cannot be fully explained by these uncertainties and that the nature of solar wind fluctuations is more complex.

Název v anglickém jazyce

Characteristics of Solar Wind Fluctuations at and below Ion Scales

Popis výsledku anglicky

Kinetic-scale fluctuations in magnetized collisionless plasmas, such as a solar wind, attract attention owing to their vital role in the dynamics of the dissipation of free energy to random particle motion. As the free energy cascades in the inertial range of turbulence, fluctuations at ion characteristic scales become more compressible. Measurements show that these fluctuations possess highly oblique propagation angles with respect to the background magnetic field and follow theoretical predictions for kinetic Alfven waves (KAWs). We performed a. large (465 cases) statistical study of normalized fluctuations of the density, bulk velocity, and magnetic field around ion gyroscale and concentrated on (i) their compressibility, (ii) the ratio of density and magnetic field fluctuations, and (iii) the ratio of density and velocity fluctuations. We find that observed fluctuations follow the two-fluid prediction for KAWs generally, but the spread of measured values around their theoretical predictions is large. The analysis of measurement uncertainties shows that the difference between the observed and predicted levels of fluctuations cannot be fully explained by these uncertainties and that the nature of solar wind fluctuations is more complex.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

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 periodika

Astrophysical Journal

ISSN

0004-637X

e-ISSN

—

Svazek periodika

879

Číslo periodika v rámci svazku

2

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

9

Strana od-do

82

Kód UT WoS článku

000474750300003

EID výsledku v databázi Scopus

2-s2.0-85071873639