History, current state, and future directions of ionospheric imaging

Bust, G. S.; Mitchell, Cathryn N.

doi:10.1029/2006rg000212

Cited by 233 publications

(213 citation statements)

References 137 publications

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“…A three-dimensional model for the ionosphere should also be possible using ray tracing for three-dimensional tomography of the ionosphere (e.g., Bust & Mitchell 2008). An indication that this may be needed for future high-accuracy Faraday depth determinations with LOFAR is the increase in the derived Faraday depth of the ISM toward B0834+06 as a function of latitude in the international station observations, see Fig.…”

Section: Discussionmentioning

confidence: 99%

Calibrating high-precision Faraday rotation measurements for LOFAR and the next generation of low-frequency radio telescopes

Sotomayor-Beltran

Sobey

Hessels

et al. 2013

A&A

123

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Faraday rotation measurements using the current and next generation of low-frequency radio telescopes will provide a powerful probe of astronomical magnetic fields. However, achieving the full potential of these measurements requires accurate removal of the time-variable ionospheric Faraday rotation contribution. We present ionFR, a code that calculates the amount of ionospheric Faraday rotation for a specific epoch, geographic location, and line-of-sight. ionFR uses a number of publicly available, GPS-derived total electron content maps and the most recent release of the International Geomagnetic Reference Field. We describe applications of this code for the calibration of radio polarimetric observations, and demonstrate the high accuracy of its modeled ionospheric Faraday rotations using LOFAR pulsar observations. These show that we can accurately determine some of the highest-precision pulsar rotation measures ever achieved. Precision rotation measures can be used to monitor rotation measure variations -either intrinsic or due to the changing line-of-sight through the interstellar medium. This calibration is particularly important for nearby sources, where the ionosphere can contribute a significant fraction of the observed rotation measure. We also discuss planned improvements to ionFR, as well as the importance of ionospheric Faraday rotation calibration for the emerging generation of low-frequency radio telescopes, such as the SKA and its pathfinders.

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Section: Discussionmentioning

confidence: 99%

Calibrating high-precision Faraday rotation measurements for LOFAR and the next generation of low-frequency radio telescopes

Sotomayor-Beltran

Sobey

Hessels

et al. 2013

A&A

123

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“…Bust et al [2004] developed an ionospheric imaging technique based on data assimilations—Ionospheric Data Assimilation Three‐Dimensional. A comprehensive review of ionospheric imaging is given in Bust and Mitchell [2008]. …”

Section: Introductionmentioning

confidence: 99%

A multiresolution inversion for imaging the ionosphere

et al. 2017

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Ionospheric tomography has been widely employed in imaging the large‐scale ionospheric structures at both quiet and storm times. However, the tomographic algorithms to date have not been very effective in imaging of medium‐ and small‐scale ionospheric structures due to limitations of uneven ground‐based data distributions and the algorithm itself. Further, the effect of the density and quantity of Global Navigation Satellite Systems data that could help improve the tomographic results for the certain algorithm remains unclear in much of the literature. In this paper, a new multipass tomographic algorithm is proposed to conduct the inversion using intensive ground GPS observation data and is demonstrated over the U.S. West Coast during the period of 16–18 March 2015 which includes an ionospheric storm period. The characteristics of the multipass inversion algorithm are analyzed by comparing tomographic results with independent ionosonde data and Center for Orbit Determination in Europe total electron content estimates. Then, several ground data sets with different data distributions are grouped from the same data source in order to investigate the impact of the density of ground stations on ionospheric tomography results. Finally, it is concluded that the multipass inversion approach offers an improvement. The ground data density can affect tomographic results but only offers improvements up to a density of around one receiver every 150 to 200 km. When only GPS satellites are tracked there is no clear advantage in increasing the density of receivers beyond this level, although this may change if multiple constellations are monitored from each receiving station in the future.

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“…In particular, IDA4D has been used to investigate the ionospheric response to major geomagnetic storms [Bust and Mitchell, 2008;Bust and Crowley, 2008], including the formation and evolution of SED. A complete mathematical derivation of the IDA4D algorithm can be found in Bust et al [2000Bust et al [ , 2004 and Bust and Datta-Barua [2012a].…”

Section: Ionospheric Data Assimilation Four-dimensionalmentioning

confidence: 99%

First storm‐time plasma velocity estimates from high‐resolution ionospheric data assimilation

2013

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This paper uses data assimilation to estimate ionospheric state during storm time at subdegree resolution. We use Ionospheric Data Assimilation Four‐Dimensional (IDA4D) to resolve the three‐dimensional time‐varying electron density gradients of the storm‐enhanced density poleward plume. By Estimating Model Parameters from Ionospheric Reverse Engineering (EMPIRE), we infer the three‐dimensional plasma velocity from the densities. EMPIRE estimates of ExB drift are made by correcting the Weimer 2000 electric potential model. This is the first time electron densities derived from GPS total electron content (TEC) data are being used to estimate field‐aligned and field‐perpendicular drifts at such high resolution, without reference to direct drift measurements. The time‐varying estimated electron densities are used to construct the ionospheric spatial decorrelation in vertical total electron content (TEC) on horizontal scales of less than 100 km. We compare slant TEC (STEC) estimates to actual STEC GPS observations, including independent unassimilated data. The IDA4D density model of the extreme ionospheric storm on 20 November 2003 shows STEC delays of up to 210 TEC units, comparable to the STEC of the GPS ground stations. Horizontal drifts from EMPIRE are predicted to be northwestward within the storm‐enhanced density plume and its boundary, turning northeast at high latitudes. These estimates compare favorably to independent Assimilative Mapping of Ionospheric Electrodynamics‐assimilated high‐latitude ExB drift estimates. Estimated and measured Defense Meteorological Satellite Program in situ drifts differ by a factor of 2–3 and in some cases have incorrect direction. This indicates that significant density rates of change and more accurate accounting for production and loss may be needed when other processes are not dominant.

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History, current state, and future directions of ionospheric imaging

Cited by 233 publications

References 137 publications

Calibrating high-precision Faraday rotation measurements for LOFAR and the next generation of low-frequency radio telescopes

Calibrating high-precision Faraday rotation measurements for LOFAR and the next generation of low-frequency radio telescopes

A multiresolution inversion for imaging the ionosphere

First storm‐time plasma velocity estimates from high‐resolution ionospheric data assimilation

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