Interplanetary Scintillation of Small Diameter Radio Sources

Hewish, A.; Scott, P. F.; Wills, D.

doi:10.1038/2031214a0

Cited by 379 publications

(230 citation statements)

References 7 publications

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“…The solar wind, the expansion of the solar corona through interplanetary space, can be probed by observing the interplanetary scintillation (IPS) of compact radio sources (Hewish et al 1964). Observations of IPS provide the ability to systematically study the solar wind at nearly all heliographic latitudes over a wide range of distances from the Sun.…”

Section: Solar Physics and Space Weathermentioning

confidence: 99%

LOFAR: The LOw-Frequency ARray

Haarlem

Wise

Gunst

et al. 2013

A&A

2,012

783

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LOFAR, the LOw-Frequency ARray, is a new-generation radio interferometer constructed in the north of the Netherlands and across europe. Utilizing a novel phased-array design, LOFAR covers the largely unexplored low-frequency range from 10-240 MHz and provides a number of unique observing capabilities. Spreading out from a core located near the village of Exloo in the northeast of the Netherlands, a total of 40 LOFAR stations are nearing completion. A further five stations have been deployed throughout Germany, and one station has been built in each of France, Sweden, and the UK. Digital beam-forming techniques make the LOFAR system agile and allow for rapid repointing of the telescope as well as the potential for multiple simultaneous observations. With its dense core array and long interferometric baselines, LOFAR achieves unparalleled sensitivity and angular resolution in the low-frequency radio regime. The LOFAR facilities are jointly operated by the International LOFAR Telescope (ILT) foundation, as an observatory open to the global astronomical community. LOFAR is one of the first radio observatories to feature automated processing pipelines to deliver fully calibrated science products to its user community. LOFAR's new capabilities, techniques and modus operandi make it an important pathfinder for the Square Kilometre Array (SKA). We give an overview of the LOFAR instrument, its major hardware and software components, and the core science objectives that have driven its design. In addition, we present a selection of new results from the commissioning phase of this new radio observatory.

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Section: Solar Physics and Space Weathermentioning

confidence: 99%

LOFAR: The LOw-Frequency ARray

Haarlem

Wise

Gunst

et al. 2013

A&A

2,012

783

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“…The radio waves emitted by a source scintillate owing to the electron density variations in an ionized plasma, such as the solar wind. A number of studies have been conducted to prove and quantify the effect of the solar wind on radio signals (Hewish et al 1964;Coles et al 1973;Coles 1996;Canals et al 2002). In these studies, the flux intensity fluctuations of the radio signal emitted by known celestial sources have been thoroughly studied at frequency bands below 2 GHz.…”

Section: Theory and Observable Valuesmentioning

confidence: 99%

Observations and analysis of phase scintillation of spacecraft signal on the interplanetary plasma

Calvés

Pogrebenko

Cimò

et al. 2014

A&A

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Aims. The phase scintillation of the European Space Agency's Venus Express (VEX) spacecraft telemetry signal was observed at X-band (λ = 3.6 cm) with a number of radio telescopes of the European Very Long Baseline Interferometry (VLBI) Network in the period 2009-2013. Methods. We found a phase fluctuation spectrum along the Venus orbit with a nearly constant spectral index of −2.42 ± 0.25 over the full range of solar elongation angles from 0 • to 45 • , which is consistent with Kolmogorov turbulence. Radio astronomical observations of spacecraft signals within the solar system give a unique opportunity to study the temporal behaviour of the signal's phase fluctuations caused by its propagation through the interplanetary plasma and the Earth's ionosphere. This gives complementary data to the classical interplanetary scintillation (IPS) study based on observations of the flux variability of distant natural radio sources. Results. We present here our technique and the results on IPS. We compare these with the total electron content for the line of sight through the solar wind. Finally, we evaluate the applicability of the presented technique to phase-referencing VLBI and Doppler observations of currently operational and prospective space missions.

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“…In order to set up the IPS observations at MEXART we used the IPS source lists reported in the first Cambridge's catalogue (Hewish, Scott, and Wills, 1964), the Ooty Radio Telescope (ORT) (Manoharan, private communication) and the Solar-Terrestrial Environment Laboratory (STEL) (Tokumaru, private communication). Table 4 shows the list of the first strong IPS sources detected by MEXART with the present configuration, using the 16 × 16 BM.…”

Section: List Of Ips Sourcesmentioning

confidence: 99%

“…The phenomenon called Interplanetary Scintillation (IPS) was discovered by Hewish, Scott, and Wills (1964). The IPS is the random intensity variation of a cosmic radio source of small diameter (<2 arc sec) caused by the scattering of the wave front as it propagates through random fluctuations in the refractive index of the turbulent interplanetary medium.…”

Section: Introductionmentioning

confidence: 99%

Observations of Interplanetary Scintillation (IPS) Using the Mexican Array Radio Telescope (MEXART)

et al. 2010

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The Mexican Array Radio Telescope (MEXART) consists of a 64 × 64 (4096) full-wavelength dipole antenna array, operating at 140 MHz, with a bandwidth of 2 MHz, occupying about 9660 square meters (69 m × 140 m) (http://www.mexart.unam.mx). This is a dedicated radio array for Interplanetary Scintillation (IPS) observations located at latitude 19°48 N, longitude 101°41 W. We characterize the performance of the system. We report the first IPS observations with the instrument, employing a Butler Matrix (BM) of 16 × 16 ports, fed by 16 east -west lines of 64 dipoles (1/4 of the total array). The BM displays a radiation pattern of 16 beams at different declinations (from −48, to +88 degrees). We present a list of 19 strong IPS radio sources (having at least 3σ in power gain) detected by the instrument. We report the power spectral analysis procedure of the intensity fluctuations. The operation of MEXART will allow us a better coverage of solar wind disturbances, complementing the data provided by the other, previously built, instruments.

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Interplanetary Scintillation of Small Diameter Radio Sources

Cited by 379 publications

References 7 publications

LOFAR: The LOw-Frequency ARray

LOFAR: The LOw-Frequency ARray

Observations and analysis of phase scintillation of spacecraft signal on the interplanetary plasma

Observations of Interplanetary Scintillation (IPS) Using the Mexican Array Radio Telescope (MEXART)

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