Power spectrum analysis of ionospheric fluctuations with the Murchison Widefield Array

Shyeh Tjing Loi, Cathryn M. Trott, Tara Murphy, Iver H. Cairns, Martin Bell, Natasha Hurley-Walker, John Morgan, Emil Lenc, A. R. Offringa, L. Feng, P. J. Hancock, D. L. Kaplan, N. Kudryavtseva, G. Bernardi, Judd Bowman, F. Briggs, R. J. Cappallo, B. E. Corey, A. A. Deshpande, D. EmrichB. M. Gaensler, R. Goeke, L. J. Greenhill, B. J. Hazelton, M. Johnston-Hollitt, J. C. Kasper, E. Kratzenberg, C. J. Lonsdale, M. J. Lynch, S. R. McWhirter, D. A. Mitchell, M. F. Morales, E. Morgan, D. Oberoi, S. M. Ord, T. Prabu, A. E E Rogers, A. Roshi, N. Udaya Shankar, K. S. Srivani, R. Subrahmanyan, S. J. Tingay, M. Waterson, R. B. Wayth, R. L. Webster, A. R. Whitney, A. Williams, C. L. Williams

Research output: Contribution to journalArticle

19 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)574-597
Number of pages24
JournalRadio Science
Volume50
Issue number7
DOIs
StatePublished - Jul 1 2015

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Keywords

  • Murchison Widefield Array
  • ionosphere
  • power spectrum

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Earth and Planetary Sciences(all)
  • Electrical and Electronic Engineering

Cite this

Loi, S. T., Trott, C. M., Murphy, T., Cairns, I. H., Bell, M., Hurley-Walker, N., Morgan, J., Lenc, E., Offringa, A. R., Feng, L., Hancock, P. J., Kaplan, D. L., Kudryavtseva, N., Bernardi, G., Bowman, J., Briggs, F., Cappallo, R. J., Corey, B. E., Deshpande, A. A., ... Williams, C. L. (2015). Power spectrum analysis of ionospheric fluctuations with the Murchison Widefield Array. Radio Science, 50(7), 574-597. https://doi.org/10.1002/2015RS005711