Power spectrum analysis of ionospheric fluctuations with the Murchison Widefield Array
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 datasets. 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 travelling ionospheric disturbances (TIDs), while others take the form of narrow, slowly-drifting bands aligned along the Earth's magnetic field.
Keywords
Cite
@article{arxiv.1506.01798,
title = {Power spectrum analysis of ionospheric fluctuations with the Murchison Widefield Array},
author = {Shyeh Tjing Loi and Cathryn M. Trott and Tara Murphy and Iver H. Cairns and Martin Bell and Natasha Hurley-Walker and John Morgan and Emil Lenc and A. R. Offringa and L. Feng and P. J. Hancock and D. L. Kaplan and N. Kudryavtseva and G. Bernardi and J. D. Bowman and F. Briggs and R. J. Cappallo and B. E. Corey and A. A. Deshpande and D. Emrich and B. M. Gaensler and R. Goeke and L. J. Greenhill and B. J. Hazelton and M. Johnston-Hollitt and J. C. Kasper and E. Kratzenberg and C. J. Lonsdale and M. J. Lynch and S. R. McWhirter and D. A. Mitchell and M. F. Morales and E. Morgan and D. Oberoi and S. M. Ord and T. Prabu and A. E. E. Rogers and A. Roshi and N. Udaya Shankar and K. S. Srivani and R. Subrahmanyan and S. J. Tingay and M. Waterson and R. B. Wayth and R. L. Webster and A. R. Whitney and A. Williams and C. L. Williams},
journal= {arXiv preprint arXiv:1506.01798},
year = {2015}
}
Comments
Accepted for publication in Radio Science