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Equatorial noise emissions observed by the DEMETER spacecraft during geomagnetic storms

Identifikátory výsledku

  • Kód výsledku v IS VaVaI

    <a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68378289%3A_____%2F16%3A00467942" target="_blank" >RIV/68378289:_____/16:00467942 - isvavai.cz</a>

  • Nalezeny alternativní kódy

    RIV/00216208:11320/16:10334394

  • Výsledek na webu

    <a href="http://dx.doi.org/10.1002/2016JA023145" target="_blank" >http://dx.doi.org/10.1002/2016JA023145</a>

  • DOI - Digital Object Identifier

    <a href="http://dx.doi.org/10.1002/2016JA023145" target="_blank" >10.1002/2016JA023145</a>

Alternativní jazyky

  • Jazyk výsledku

    angličtina

  • Název v původním jazyce

    Equatorial noise emissions observed by the DEMETER spacecraft during geomagnetic storms

  • Popis výsledku v původním jazyce

    Equatorial noise emissions are electromagnetic waves routinely observed in the equatorial region of the inner magnetosphere at frequencies between the proton cyclotron frequency and the lower hybrid frequency. Their observations are, however, typically limited to radial distances larger than about 2RE. We use the data measured by the low-altitude DEMETER spacecraft (altitude of about 700 km) to confirm that during periods of enhanced geomagnetic activity, these emissions penetrate down to low radial distances and eventually become a dominant wave emission close to the proton cyclotron frequency in the equatorial region. Wave data obtained during six intense geomagnetic storms (Dst < 100 nT) are analyzed. It is shown that during the analyzed time intervals, the daytime wave activity within about 20° from the geomagnetic equator is significantly enhanced, while the nightside wave activity shows a weaker increase at lower frequencies. Multicomponent wave data allow us to determine dayside wave propagation parameters. It is shown that the waves are nearly linearly polarized and their wave vector directions are almost perpendicular to the ambient Earth's magnetic field, as it has been previously observed for equatorial noise emissions. Finally, we analyze the dependence of the equatorial wave intensity at the proton cyclotron frequency on Dst and AE geomagnetic indices, and we demonstrate that the dayside wave intensity increases by as much as 3 orders of magnitude during severely disturbed periods.

  • Název v anglickém jazyce

    Equatorial noise emissions observed by the DEMETER spacecraft during geomagnetic storms

  • Popis výsledku anglicky

    Equatorial noise emissions are electromagnetic waves routinely observed in the equatorial region of the inner magnetosphere at frequencies between the proton cyclotron frequency and the lower hybrid frequency. Their observations are, however, typically limited to radial distances larger than about 2RE. We use the data measured by the low-altitude DEMETER spacecraft (altitude of about 700 km) to confirm that during periods of enhanced geomagnetic activity, these emissions penetrate down to low radial distances and eventually become a dominant wave emission close to the proton cyclotron frequency in the equatorial region. Wave data obtained during six intense geomagnetic storms (Dst < 100 nT) are analyzed. It is shown that during the analyzed time intervals, the daytime wave activity within about 20° from the geomagnetic equator is significantly enhanced, while the nightside wave activity shows a weaker increase at lower frequencies. Multicomponent wave data allow us to determine dayside wave propagation parameters. It is shown that the waves are nearly linearly polarized and their wave vector directions are almost perpendicular to the ambient Earth's magnetic field, as it has been previously observed for equatorial noise emissions. Finally, we analyze the dependence of the equatorial wave intensity at the proton cyclotron frequency on Dst and AE geomagnetic indices, and we demonstrate that the dayside wave intensity increases by as much as 3 orders of magnitude during severely disturbed periods.

Klasifikace

  • Druh

    J<sub>x</sub> - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

  • CEP obor

    BL - Fyzika plasmatu a výboje v plynech

  • OECD FORD obor

Návaznosti výsledku

  • Projekt

    Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

  • Návaznosti

    I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Ostatní

  • Rok uplatnění

    2016

  • Kód důvěrnosti údajů

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

Údaje specifické pro druh výsledku

  • Název periodika

    Journal of Geophysical Research: Space Physics

  • ISSN

    2169-9380

  • e-ISSN

  • Svazek periodika

    121

  • Číslo periodika v rámci svazku

    10

  • Stát vydavatele periodika

    US - Spojené státy americké

  • Počet stran výsledku

    14

  • Strana od-do

    9744-9757

  • Kód UT WoS článku

    000388965900029

  • EID výsledku v databázi Scopus

    2-s2.0-84991608267