A LOFAR observation of ionospheric scintillation from two simultaneous travelling ionospheric disturbances
Journal article, 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.
travelling ionospheric disturbances
Ionospheric scintillation
instability mechanisms
Author
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 (Operation) Ltd
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
German Research Centre for Geosciences (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 Society
Bartosz Dabrowski
University of Warmia and Mazury in Olsztyn
Sieds Damstra
Netherlands Institute for Radio Astronomy (ASTRON)
Francesco de Gasperin
University of 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
Leiden University
Jean-Matthias Griessmeier
University of Orléans
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 Brussel (VUB)
Radboud University
Marco Iacobelli
Netherlands Institute for Radio Astronomy (ASTRON)
Huib T. Intema
Leiden University
Leon V. E. Koopmans
University of Groningen
Peter Maat
Netherlands Institute for Radio Astronomy (ASTRON)
Gottfried Mann
Leibniz Institute for Astrophysics Potsdam
Anna Nelles
Deutsches Elektronen-Synchrotron (DESY)
University of Erlangen-Nuremberg (FAU)
Harm Paas
University of Groningen
Vishambhar N. Pandey
Netherlands Institute for Radio Astronomy (ASTRON)
University of Groningen
Wolfgang Reich
Max Planck Society
Antonia Rowlinson
Netherlands Institute for Radio Astronomy (ASTRON)
University of Amsterdam
Mark Ruiter
Netherlands Institute for Radio Astronomy (ASTRON)
Dominik J. Schwarz
Bielefeld University
Maciej Serylak
South African Radio Astronomy Observatory (SARAO)
University of the Western Cape
Aleksander Shulevski
University of Amsterdam
Oleg M. Smirnov
South African Radio Astronomy Observatory (SARAO)
Rhodes University
Marian Soida
Jagiellonian University in Kraków
Matthias Steinmetz
Leibniz Institute for Astrophysics Potsdam
Satyendra Thoudam
Khalifa University
Maria Carmen Toribio Perez
Chalmers, Space, Earth and Environment, Onsala Space Observatory
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 Institute for Astrophysics Potsdam
Ralph A. M. J. Wijers
University of Amsterdam
Olaf Wucknitz
Max Planck Society
Philippe Zarka
LESIA - Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique
Centre national de la recherche scientifique (CNRS)
Pietro Zucca
Netherlands Institute for Radio Astronomy (ASTRON)
Journal of Space Weather and Space Climate
2115-7251 (eISSN)
Vol. 10 10Subject Categories
Astronomy, Astrophysics and Cosmology
Geophysics
Fusion, Plasma and Space Physics
DOI
10.1051/swsc/2020010