A LOFAR observation of ionospheric scintillation from two simultaneous travelling ionospheric disturbances
Artikel i vetenskaplig tidskrift, 2020
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 similar to 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 similar to 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.
instability mechanisms
travelling ionospheric disturbances
Ionospheric scintillation
Författare
Richard A. Fallows
Netherlands Institute for Radio Astronomy (ASTRON)
Biagio Forte
University of Bath
Ivan Astin
University of Bath
Tom Allbrook
University of Bath
BAE Systems
Alex Arnold
University of Bath
Alan Wood
Nottingham Trent University
Gareth Dorrian
University of Birmingham
Maaijke Mevius
Netherlands Institute for Radio Astronomy (ASTRON)
Hanna Rothkaehl
Polish Academy of Sciences
Barbara Matyjasiak
Polish Academy of Sciences
Andrzej Krankowski
University of Warmia and Mazury in Olsztyn
James M. Anderson
Technische Universität Berlin
Deutsches GeoForschungsZentrum (GFZ)
Ashish Asgekar
Shell Technology Center
I. Max Avruch
Sci & Technol BV
Mark Bentum
Netherlands Institute for Radio Astronomy (ASTRON)
Mario M. Bisi
STFC Rutherford Appleton Laboratory
Harvey R. Butcher
Australian National University
Benedetta Ciardi
Max-Planck-Gesellschaft
Bartosz Dabrowski
University of Warmia and Mazury in Olsztyn
Sieds Damstra
Netherlands Institute for Radio Astronomy (ASTRON)
Francesco de Gasperin
Universität Hamburg
Sven Duscha
Netherlands Institute for Radio Astronomy (ASTRON)
Jochen Eisloeffel
Thüringer Landessternwarte Tautenburg
Thomas M. O. Franzen
Netherlands Institute for Radio Astronomy (ASTRON)
Michael A. Garrett
University of Manchester
Universiteit Leiden
Jean-Matthias Griessmeier
Universite d'Orleans
Andre W. Gunst
Netherlands Institute for Radio Astronomy (ASTRON)
Matthias Hoeft
Thüringer Landessternwarte Tautenburg
Jorg R. Horandel
National Institute for Subatomic Physics (NIKHEF)
Vrije Universiteit Brüssel (VUB)
Radboud Universiteit
Marco Iacobelli
Netherlands Institute for Radio Astronomy (ASTRON)
Huib T. Intema
Universiteit Leiden
Leon V. E. Koopmans
Rijksuniversiteit Groningen
Peter Maat
Netherlands Institute for Radio Astronomy (ASTRON)
Gottfried Mann
Leibniz-Gemeinschaft
Anna Nelles
Deutsches Elektronen-Synchrotron (DESY)
Friedrich-Alexander-Universität Erlangen Nurnberg (FAU)
Harm Paas
Rijksuniversiteit Groningen
Vishambhar N. Pandey
Rijksuniversiteit Groningen
Netherlands Institute for Radio Astronomy (ASTRON)
Wolfgang Reich
Max-Planck-Gesellschaft
Antonia Rowlinson
Universiteit Van Amsterdam
Netherlands Institute for Radio Astronomy (ASTRON)
Mark Ruiter
Netherlands Institute for Radio Astronomy (ASTRON)
Dominik J. Schwarz
Universität Bielefeld
Maciej Serylak
South African Radio Astronomy Observatory (SARAO)
University of the Western Cape
Aleksander Shulevski
Universiteit Van Amsterdam
Oleg M. Smirnov
Rhodes University
South African Radio Astronomy Observatory (SARAO)
Marian Soida
Uniwersytet Jagiellonski w Krakowie
Matthias Steinmetz
Leibniz-Gemeinschaft
Satyendra Thoudam
Khalifa University
Maria Carmen Toribio Perez
Chalmers, Rymd-, geo- och miljövetenskap, Onsala rymdobservatorium
Arnold van Ardenne
Netherlands Institute for Radio Astronomy (ASTRON)
Ilse M. van Bemmel
Joint Institute for VLBI in Europe (JIVE)
Matthijs H. D. van der Wiel
Netherlands Institute for Radio Astronomy (ASTRON)
Michiel P. van Haarlem
Netherlands Institute for Radio Astronomy (ASTRON)
Rene C. Vermeulen
Netherlands Institute for Radio Astronomy (ASTRON)
Christian Vocks
Leibniz-Gemeinschaft
Ralph A. M. J. Wijers
Universiteit Van Amsterdam
Olaf Wucknitz
Max-Planck-Gesellschaft
Philippe Zarka
Centre national de la recherche scientifique (CNRS)
LESIA - Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique
Pietro Zucca
Netherlands Institute for Radio Astronomy (ASTRON)
Journal of Space Weather and Space Climate
2115-7251 (eISSN)
Vol. 10 10Ämneskategorier (SSIF 2011)
Astronomi, astrofysik och kosmologi
Geofysik
Fusion, plasma och rymdfysik
DOI
10.1051/swsc/2020010