A Study on Low Frequency Electromagnetic Cyclotron Waves in the Solar Wind

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F22%3A10457961" target="_blank" >RIV/00216208:11320/22:10457961 - isvavai.cz</a>

Výsledek na webu

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=ELXwp43HFH" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=ELXwp43HFH</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1088/1674-4527/ac67bc" target="_blank" >10.1088/1674-4527/ac67bc</a>

Jazyk výsledku

angličtina

Název v původním jazyce

A Study on Low Frequency Electromagnetic Cyclotron Waves in the Solar Wind

Popis výsledku v původním jazyce

According to Wind observations between 2005 and 2015, this paper investigates the dependences of the occurrence of low frequency electromagnetic cyclotron waves (ECWs) on the plasma parameters, the solar cycle, and the orientations of alpha-proton drift velocity ( V ( d )) and the ambient magnetic field ( B ). The occurrence rates of ECWs with respect to six plasma parameters are calculated. Results show that the preferential conditions for generation of left-handed (LH) ECWs are higher proton temperature (T ( p )), higher proton velocity (V ( p )), lower proton density (N ( p )), stronger proton temperature anisotropy (T (perpendicular to)/T (parallel to)), higher normalized alpha-proton drift velocity (V ( d )/V (A)), and higher normalized alpha particle density (N ( alpha )/N ( p )), where T (perpendicular to) and T (parallel to) refer to proton temperatures perpendicular and parallel to B , and V (A) is the local Alfven velocity. For right-handed (RH) ECWs, however, the dependences on these plasma parameters are not obvious. On the other hand, it is found that the occurrence rate of LH ECWs increases as the sunspot number decreases, and decreases as the sunspot number increases. Further investigation shows that the increased occurrence rate of LH ECWs is accompanied by an increase in the medians of V ( p ), V ( d )/V (A), and N ( alpha )/N ( p ). For RH ECWs, the occurrence rate appears to be nearly unrelated to the sunspot number, suggesting a negligible correlation with the solar cycle. In addition, a modified angle is introduced to include the factors of orientation of B (anti-sunward or sunward) and angle between V ( d ) and B , simultaneously. It is found that the occurrence of LH ECWs has the strong preferential condition that V ( d ) is anti-sunward, while a different situation arises for RH ECWs. These results are discussed in the context of the temperature-anisotropy-driven instabilities with the effect of alpha particles.

Název v anglickém jazyce

A Study on Low Frequency Electromagnetic Cyclotron Waves in the Solar Wind

Popis výsledku anglicky

According to Wind observations between 2005 and 2015, this paper investigates the dependences of the occurrence of low frequency electromagnetic cyclotron waves (ECWs) on the plasma parameters, the solar cycle, and the orientations of alpha-proton drift velocity ( V ( d )) and the ambient magnetic field ( B ). The occurrence rates of ECWs with respect to six plasma parameters are calculated. Results show that the preferential conditions for generation of left-handed (LH) ECWs are higher proton temperature (T ( p )), higher proton velocity (V ( p )), lower proton density (N ( p )), stronger proton temperature anisotropy (T (perpendicular to)/T (parallel to)), higher normalized alpha-proton drift velocity (V ( d )/V (A)), and higher normalized alpha particle density (N ( alpha )/N ( p )), where T (perpendicular to) and T (parallel to) refer to proton temperatures perpendicular and parallel to B , and V (A) is the local Alfven velocity. For right-handed (RH) ECWs, however, the dependences on these plasma parameters are not obvious. On the other hand, it is found that the occurrence rate of LH ECWs increases as the sunspot number decreases, and decreases as the sunspot number increases. Further investigation shows that the increased occurrence rate of LH ECWs is accompanied by an increase in the medians of V ( p ), V ( d )/V (A), and N ( alpha )/N ( p ). For RH ECWs, the occurrence rate appears to be nearly unrelated to the sunspot number, suggesting a negligible correlation with the solar cycle. In addition, a modified angle is introduced to include the factors of orientation of B (anti-sunward or sunward) and angle between V ( d ) and B , simultaneously. It is found that the occurrence of LH ECWs has the strong preferential condition that V ( d ) is anti-sunward, while a different situation arises for RH ECWs. These results are discussed in the context of the temperature-anisotropy-driven instabilities with the effect of alpha particles.

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

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2022

Kód důvěrnosti údajů

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

Název periodika

Research in Astronomy and Astrophysics

ISSN

1674-4527

e-ISSN

2397-6209

Svazek periodika

22

Číslo periodika v rámci svazku

6

Stát vydavatele periodika

CN - Čínská lidová republika

Počet stran výsledku

9

Strana od-do

065007

Kód UT WoS článku

000805141500001

EID výsledku v databázi Scopus

2-s2.0-85131448754