Počet záznamů: 1  

An improved sheath impedance model for the Van Allen Probes EFW instrument: Effects of the spin axis antenna

  1. 1.
    SYSNO ASEP0476047
    Druh ASEPJ - Článek v odborném periodiku
    Zařazení RIVJ - Článek v odborném periodiku
    Poddruh JČlánek ve WOS
    NázevAn improved sheath impedance model for the Van Allen Probes EFW instrument: Effects of the spin axis antenna
    Tvůrce(i) Hartley, D. P. (US)
    Kletzing, C. A. (US)
    Kurth, W. S. (US)
    Hospodarsky, G. B. (US)
    Bounds, S. R. (US)
    Averkamp, T. F. (US)
    Bonnell, J. W. (US)
    Santolík, Ondřej (UFA-U) RID, ORCID
    Wygant, J. R. (US)
    Celkový počet autorů9
    Zdroj.dok.Journal of Geophysical Research-Space Physics. - : Wiley - ISSN 2169-9380
    Roč. 122, č. 4 (2017), s. 4420-4429
    Poč.str.10 s.
    Forma vydáníTištěná - P
    Jazyk dok.eng - angličtina
    Země vyd.US - Spojené státy americké
    Klíč. slovaantenna sheath impedance ; electric field ; Van Allen Probes ; EFW ; EMFISIS ; whistler mode waves
    Vědní obor RIVBL - Fyzika plazmatu a výboje v plynech
    Obor OECDFluids and plasma physics (including surface physics)
    CEPLH15304 GA MŠMT - Ministerstvo školství, mládeže a tělovýchovy
    Institucionální podporaUFA-U - RVO:68378289
    UT WOS000401340800038
    EID SCOPUS85017619056
    DOI10.1002/2016JA023597
    AnotaceA technique to quantitatively determine the sheath impedance of the Van Allen Probes Electric Field and Waves (EFW) instrument is presented. This is achieved, for whistler mode waves, through a comparison between the total electric field wave power spectra calculated from magnetic field observations and cold plasma theory and the total electric field wave power measured by the EFW spherical double probes instrument. In a previous study, a simple density-dependent sheath impedance model was developed in order to account for the differences between the observed and calculated wave electric field. The current study builds on this previous work by investigating the remaining discrepancies, identifying their cause, and developing an improved sheath impedance correction. Analysis reveals that anomalous gains are caused by the spin axis antennas measuring too much electric field at specific densities and frequencies. This is accounted for in an improved sheath impedance model by introducing a density-dependent function describing the relative effective length of the probe separation, Leff, in addition to the sheath capacitance and resistance values previously calculated. Leff values vary between between 0.5 and 1.2, with values >1 accounting for the anomalous gains and values <1 accounting for the shorting effect at low densities. Applying this improved sheath impedance model results in a significant increase in the agreement level between observed and calculated electric field power spectra and wave powers over the previous model.
    PracovištěÚstav fyziky atmosféry
    KontaktKateřina Adamovičová, adamovicova@ufa.cas.cz, Tel.: 272 016 012 ; Kateřina Potužníková, kaca@ufa.cas.cz, Tel.: 272 016 019
    Rok sběru2018
Počet záznamů: 1  

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