A LOFAR observation of ionospheric scintillation from two simultaneous travelling ionospheric disturbances
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Le résumé fourni par la source
This paper presents the results from one of the first observations of ionospheric scintillation taken using the Low-Frequency Array (LOFAR). The observation was of the strong natural radio source Cassiopeia A, taken overnight on 18–19 August 2013, and exhibited moderately strong scattering effects in dynamic spectra of intensity received across an observing bandwidth of 10–80 MHz. Delay-Doppler spectra (the 2-D FFT of the dynamic spectrum) from the first hour of observation showed two discrete parabolic arcs, one with a steep curvature and the other shallow, which can be used to provide estimates of the distance to, and velocity of, the scattering plasma. A cross-correlation analysis of data received by the dense array of stations in the LOFAR “core” reveals two different velocities in the scintillation pattern: a primary velocity of ~20–40 ms−1 with a north-west to south-east direction, associated with the steep parabolic arc and a scattering altitude in the F-region or higher, and a secondary velocity of ~110 ms−1 with a north-east to south-west direction, associated with the shallow arc and a scattering altitude in the D-region. Geomagnetic activity was low in the mid-latitudes at the time, but a weak sub-storm at high latitudes reached its peak at the start of the observation. An analysis of Global Navigation Satellite Systems (GNSS) and ionosonde data from the time reveals a larger-scale travelling ionospheric disturbance (TID), possibly the result of the high-latitude activity, travelling in the north-west to south-east direction, and, simultaneously, a smaller-scale TID travelling in a north-east to south-west direction, which could be associated with atmospheric gravity wave activity. The LOFAR observation shows scattering from both TIDs, at different altitudes and propagating in different directions. To the best of our knowledge this is the first time that such a phenomenon has been reported.
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Le contrôle bibliographique ouvert
DOI retrouvé dans Crossref DOI retrouvé ; titre concordant.
- Titre Crossref
- A LOFAR observation of ionospheric scintillation from two simultaneous travelling ionospheric disturbances
- Date Crossref
- 01/01/2020
- Éditeur
- EDP Sciences
- Type
- journal-article
Ce recoupement confirme des métadonnées liées au DOI. Il ne confirme ni la méthode ni les conclusions de l’étude, et il ne compte pas comme une seconde source scientifique indépendante.
Où se fait cette recherche
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Netherlands Institute for Radio Astronomy pays non établi dans la noticeInstitution
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University of Bath Department of Electronic and Electrical Engineering pays non établi dans la noticeUniversité ou école supérieure
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Nottingham Trent University pays non établi dans la noticeUniversité ou école supérieure
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University of Birmingham pays non établi dans la noticeUniversité ou école supérieure
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Centrum Badań Kosmicznych pays non établi dans la noticeStructure de recherche
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Polish Academy of Sciences pays non établi dans la noticeOrganisme public
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University of Warmia and Mazury in Olsztyn Space Radio-Diagnostics Research Centre pays non établi dans la noticeUniversité ou école supérieure
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GFZ Helmholtz Centre for Geosciences pays non établi dans la noticeStructure de recherche
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Technische Universität Berlin pays non établi dans la noticeUniversité ou école supérieure
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Shell (India) pays non établi dans la noticeEntreprise
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Rutherford Appleton Laboratory UKRI STFC pays non établi dans la noticeStructure de recherche
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Australian National University pays non établi dans la noticeUniversité ou école supérieure
Netherlands Institute for Radio Astronomy, Department of Electronic and Electrical Engineering — University of Bath et Nottingham Trent University, avec 9 autres affiliations. Pays d’affiliation : Afrique du Sud.
Une affiliation ne permet pas de déduire la nationalité d’un auteur.