Quasiperiodic Whistler Mode Emissions Observed by the Van Allen Probes Spacecraft

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378289%3A_____%2F18%3A00506364" target="_blank" >RIV/68378289:_____/18:00506364 - isvavai.cz</a>

Výsledek na webu

<a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018JA026058" target="_blank" >https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018JA026058</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1029/2018JA026058" target="_blank" >10.1029/2018JA026058</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Quasiperiodic Whistler Mode Emissions Observed by the Van Allen Probes Spacecraft

Popis výsledku v původním jazyce

Quasiperiodic (QP) emissions are whistler mode electromagnetic waves observed in the inner magnetosphere that exhibit a QP time modulation of the wave intensity. We analyze 768 QP events observed during the first 5 years of the operation of the Van Allen Probes spacecraft (September 2012 to October 2017). Multicomponent wave measurements performed in the equatorial region, where the emissions are likely generated, are used to reveal new experimental information about their properties. We show that the events are observed nearly exclusively inside the plasmasphere. Wave frequencies are mostly between about 0.5 and 4 kHz. The events observed at larger radial distances and on the duskside tend to have slightly lower frequencies than the emissions observed elsewhere. The maximum event frequencies are limited by half of the equatorial electron gyrofrequency, suggesting the importance of wave ducting. Modulation periods are typically between about 0.5 and 5 min, and they increase with the in situ measured plasma number density. This increase is consistent with the main mechanisms suggested to explain the origin of the QP modulation. Two-point measurements performed by the Van Allen Probes are used to estimate a typical spatial extent of the emissions to about 1 R-E in radial distance and 1.5 hr in magnetic local time. Detailed wave analysis shows that the emissions are right-hand circularly polarized, and they usually come from several different directions simultaneously. They, however, predominantly propagate at rather low wave normal angles and away from the geomagnetic equator.

Název v anglickém jazyce

Quasiperiodic Whistler Mode Emissions Observed by the Van Allen Probes Spacecraft

Popis výsledku anglicky

Quasiperiodic (QP) emissions are whistler mode electromagnetic waves observed in the inner magnetosphere that exhibit a QP time modulation of the wave intensity. We analyze 768 QP events observed during the first 5 years of the operation of the Van Allen Probes spacecraft (September 2012 to October 2017). Multicomponent wave measurements performed in the equatorial region, where the emissions are likely generated, are used to reveal new experimental information about their properties. We show that the events are observed nearly exclusively inside the plasmasphere. Wave frequencies are mostly between about 0.5 and 4 kHz. The events observed at larger radial distances and on the duskside tend to have slightly lower frequencies than the emissions observed elsewhere. The maximum event frequencies are limited by half of the equatorial electron gyrofrequency, suggesting the importance of wave ducting. Modulation periods are typically between about 0.5 and 5 min, and they increase with the in situ measured plasma number density. This increase is consistent with the main mechanisms suggested to explain the origin of the QP modulation. Two-point measurements performed by the Van Allen Probes are used to estimate a typical spatial extent of the emissions to about 1 R-E in radial distance and 1.5 hr in magnetic local time. Detailed wave analysis shows that the emissions are right-hand circularly polarized, and they usually come from several different directions simultaneously. They, however, predominantly propagate at rather low wave normal angles and away from the geomagnetic equator.

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

2018

Kód důvěrnosti údajů

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

Název periodika

Journal of Geophysical Research: Space Physics

ISSN

2169-9380

e-ISSN

—

Svazek periodika

123

Číslo periodika v rámci svazku

11

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

14

Strana od-do

8969-8982

Kód UT WoS článku

000453227400006

EID výsledku v databázi Scopus

2-s2.0-85055951159