Power spectrum analysis of ionospheric fluctuations with the Murchison Widefield Array

Journal
Date Issued
2015
Author(s)
Loi, Shyeh Tjing
•
Trott, Cathryn M.
•
Murphy, Tara
•
Cairns, Iver H.
•
Bell, Martin
•
Hurley-Walker, Natasha
•
Morgan, John
•
Lenc, Emil
•
Offringa, A. R.
•
Feng, L.
•
Hancock, P. J.
•
Kaplan, D. L.
•
Kudryavtseva, N.
•
•
Bowman, J. D.
•
Briggs, F.
•
Cappallo, R. J.
•
Corey, B. E.
•
Deshpande, A. A.
•
Emrich, D.
•
Gaensler, B. M.
•
Goeke, R.
•
Greenhill, L. J.
•
Hazelton, B. J.
•
Johnston-Hollitt, M.
•
Kasper, J. C.
•
Kratzenberg, E.
•
Lonsdale, C. J.
•
Lynch, M. J.
•
McWhirter, S. R.
•
Mitchell, D. A.
•
Morales, M. F.
•
Morgan, E.
•
Oberoi, D.
•
Ord, S. M.
•
Prabu, T.
•
Rogers, A. E. E.
•
Roshi, A.
•
Shankar, N. Udaya
•
Srivani, K. S.
•
Subrahmanyan, R.
•
Tingay, S. J.
•
Waterson, M.
•
Wayth, R. B.
•
Webster, R. L.
•
Whitney, A. R.
•
Williams, A.
•
Williams, C. L.
DOI
Description
Acknowledgments The data supporting this paper are available upon request submitted via email to the corresponding author at sloi5113@uni.sydney.edu.au . This scientific work makes use of the Murchison Radio‐astronomy Observatory. We acknowledge the Wajarri Yamatji people as the traditional owners of the Observatory site. Support for the MWA comes from the U.S. National Science Foundation (grants AST‐0457585, PHY‐0835713, CAREER‐0847753, and AST‐0908884), the Australian Research Council (LIEF grants LE0775621 and LE0882938), the U.S. Air Force Office of Scientic Research (grant FA9550‐0510247), and the Centre for All‐sky Astrophysics (an Australian Research Council Centre of Excellence funded by grant CE110001020). Support is also provided by the Smithsonian Astrophysical Observatory, the MIT School of Science, the Raman Research Institute, the Australian National University, and the Victoria University of Wellington (via grant MED‐E1799 from the New Zealand Ministry of Economic Development and an IBM Shared University Research grant). The Australian Federal government provides additional support via the National Collaborative Research Infrastructure Strategy, Education Investment Fund, and the Australia India Strategic Research Fund, and Astronomy Australia Limited, under contract to Curtin University. We acknowledge the iVEC Petabyte Data Store, the Initiative in Innovative Computing and the CUDA Center for Excellence sponsored by NVIDIA at Harvard University, and the International Centre for Radio Astronomy Research (ICRAR), a Joint Venture of Curtin University and The University of Western Australia, funded by the Western Australian State government. I.H.C. acknowledges the support of grants DP110101587 and DP140103933. C.M.T. is supported by an Australian Research Council DECRA award, DE140100316. D.L.K. acknowledges the support of grant AST‐1412421.
Abstract
Low-frequency, wide field-of-view (FOV) radio telescopes such as the Murchison Widefield Array (MWA) enable the ionosphere to be sampled at high spatial completeness. We present the results of the first power spectrum analysis of ionospheric fluctuations in MWA data, where we examined the position offsets of radio sources appearing in two data sets. The refractive shifts in the positions of celestial sources are proportional to spatial gradients in the electron column density transverse to the line of sight. These can be used to probe plasma structures and waves in the ionosphere. The regional (10-100 km) scales probed by the MWA, determined by the size of its FOV and the spatial density of radio sources (typically thousands in a single FOV), complement the global (100-1000 km) scales of GPS studies and local (0.01-1 km) scales of radar scattering measurements. Our data exhibit a range of complex structures and waves. Some fluctuations have the characteristics of traveling ionospheric disturbances, while others take the form of narrow, slowly drifting bands aligned along the Earth's magnetic field.
Volume
50
Issue
7
Start page
574
Uri
Url
Issn Identifier
0048-6604
Ads BibCode
2015RaSc...50..574L
Rights
open.access
File(s)
Loading...
Thumbnail Image
Name

Loi2015c.pdf

Description
Pdf editoriale
Size

2.77 MB

Format

Adobe PDF

Checksum (MD5)

6f93399fd49a6b760df1958e4513b24f