Observations of interplanetary scintillation with a single-station mode at Urumqi

Liu, Li-Jia; Zhang, Xizhen; Li, Jianbin; Manoharan, P. K.; Liu, Zhiyong; Peng, Bo

doi:10.1088/1674-4527/10/6/007

Cited by 7 publications

(7 citation statements)

References 13 publications

(10 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, the IPS used in this study, at 327 MHz, can probe turbulence scales below 400 km. A suitable calibration of the temporal spectrum of intensity fluctuations can provide the solar wind speed (e.g., Manoharan & Ananthakrishnan 1990;Manoharan et al 2000;Tokumaru et al 1994Tokumaru et al , 2011Yamauchi et al 1996Yamauchi et al , 1998Liu et al 2010) and the scintillation index, m (e.g., Coles 1978;Manoharan 1993;Asai et al 1998). The scintillation index, m, is a measure of electron-density turbulence in the solar wind (m 2 ∼ δN 2 e (z) dz), along the line of sight (z) to the radio source (e.g., Manoharan 1993;Manoharan et al 2000).…”

Section: Interplanetary Scintillationmentioning

confidence: 99%

“…For an IPS observation in the weak-scattering regime, a suitable calibration of the temporal power spectrum of intensity fluctuations, having sufficient signalto-noise ratio (i.e., 15 dB), can provide the speed of the solar wind (Manoharan & Ananthakrishnan 1990;Manoharan et al 2000;Tokumaru et al 1994Tokumaru et al , 2011Yamauchi et al 1996Yamauchi et al , 1998Liu et al 2010). Figure 6 shows the 'latitude-year' distribution of solar wind speed estimates obtained from the IPS data collected from the Ooty Radio Telescope, as it was displayed in the plots of density and density turbulence (Figures 4 and 5).…”

Section: Solar Cycle Changes Of Solar Wind Speedmentioning

confidence: 99%

See 1 more Smart Citation

Three-Dimensional Evolution of Solar Wind During Solar Cycles 22–24

Manoharan

2012

ApJ

View full text Add to dashboard Cite

This paper presents the analysis of three-dimensional evolution of solar wind density turbulence and speed at various levels of solar activity between solar cycles 22 and 24. The solar wind data used in this study has been obtained from interplanetary scintillation (IPS) measurements made at the Ooty Radio Telescope, operating at 327 MHz. Results show that (i) on the average, there was a downward trend in density turbulence from the maximum of cycle 22 to the deep minimum phase of cycle 23; (2) the scattering diameter of the corona around the Sun shrunk steadily towards the Sun, starting from 2003 to the smallest size at the deepest minimum, and it corresponded to a reduction of ∼50% in density turbulence between maximum and minimum phases of cycle 23; (3) The latitudinal distribution of solar wind speed was significantly different between minima of cycles 22 and 23. At the minimum phase of solar cycle 22, when the underlying solar magnetic field was simple and nearly dipole in nature, the high-speed streams were observed from poles to ∼30 • latitudes in both hemispheres. In contrast, in the long-decay phase of cycle 23, the sources of high-speed wind at both poles, in accordance with the weak polar fields, occupied narrow latitude belts from poles to ∼60 • latitudes. Moreover, in agreement with the large amplitude of heliospheric current sheet, the low-speed wind prevailed the low-and mid-latitude regions of the heliosphere. (4) At the transition phase between cycles 23 and 24, the high levels of density and density turbulence were observed close to the heliospheric equator and the low-speed speed wind extended from equatorial-to mid-latitude regions. The above results in comparison with Ulysses and other in-situ measurements suggest that the source of solar wind has changed globally, with the important implication that the supply of mass and energy from the Sun to the interplanetary space has significantly reduced in the prolonged period of low level of solar activity. The IPS results are consistent with the onset and growth of the current solar cycle 24, starting from middle of 2009. However, the width of the high-speed wind at the northern high latitudes has almost disappeared and indicates that the ascending phase of the current cycle has almost reached near to the maximum phase at the northern hemisphere of the Sun. But, in the southern part of the hemisphere, the solar activity has yet to develop and/or increase.

show abstract

Section: Interplanetary Scintillationmentioning

confidence: 99%

Section: Solar Cycle Changes Of Solar Wind Speedmentioning

confidence: 99%

Three-Dimensional Evolution of Solar Wind During Solar Cycles 22–24

Manoharan

2012

ApJ

View full text Add to dashboard Cite

show abstract

“…A new IPS observing system has been established at Urumqi Astronomical Observatory (UAO), China, and a series of experimental observations have been successfully carried out from May to December 2008, at bands of 327/611 MHz and 2.3/8.4 GHz (Liu et al 2010).…”

Section: New Ips Facilitiesmentioning

confidence: 99%

Commission 49: Interplanetary Plasma and Heliosphere

Gopalswamy¹,

Mann²,

Bougeret³

et al. 2011

Proc. IAU

View full text Add to dashboard Cite

Commission 49 (Interplanetary Plasma and Heliosphere) is part of IAU Division II (Sun and Heliosphere). The research topics include large-scale solar disturbances such as coronal mass ejections (CMEs), shocks, and corotating interaction regions (CIRs) propagating into the heliosphere. The disturbances propagate through the solar wind, which essentially defines the heliosphere. The solar disturbances provide large-scale laboratory to study plasma processes over various time and spatial scales, the highest spatial scale being the size of the heliosphere itself (~100 AU). These solar disturbances are related to solar activity in the form of active regions and coronal holes. Solar eruptions are accompanied by particle acceleration and the particles can be hazardous to life on earth in various ways from modifying the ionosphere to damaging space technology and increasing lifetime radiation dosage to astronauts and airplane crew. Particle acceleration in solar eruptions poses fundamental physics questions because the underlying mechanisms are not fully understood. One of important processes is the particle acceleration by shocks, which occurs throughout the heliosphere. The heliosphere has both neutral and ionized material, with interesting interaction between the two components.

show abstract

“…The four-station system in Japan is a representative of the multi-station system, and it can measure the radial solar wind projection (Asai et al 1995). Due to some practical reasons, most IPS facilities have adopted the single station system, like the ORT (Manoharan 2010), MWA (Morgan et al 2018;Chhetri et al 2018a,b) and the 25m radio telescope in Urumqi, Xinjiang, China (Liu et al 2010). For the single station observations, two analysis modes are available, dependent on the system observing capabilities, namely the single-frequency (SSSF) analysis mode, and the dual-frequency (SSDF) analysis mode (Zhang 2007).…”

Section: Introductionmentioning

confidence: 99%

A Pilot Study of Interplanetary Scintillation with FAST

Liu,

Peng,

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

Observations of Interplanetary Scintillation (IPS) are an efficient remote-sensing method to study the solar wind and inner heliosphere. From 2016 to 2018, some distinctive observations of IPS sources like 3C 286 and 3C 279 were accomplished with the Five-hundred-meter Aperture Spherical radio Telescope (FAST), the largest single-dish telescope in the world. Due to the 270-1620 MHz wide frequency coverage of the Ultra-Wideband (UWB) receiver, one can use both single-frequency and dual-frequency analyses to determine the projected velocity of the solar wind. Moreover, based on the extraordinary sensitivity owing to the large collecting surface area of FAST, we can observe weak IPS signals. With the advantages of both the wider frequency coverage and high sensitivity, also with our radio frequency interference (RFI) mitigation strategy and an optimized model-fitting method developed, in this paper, we analyze the fitting confidence intervals of the solar wind velocity, and present some preliminary results achieved using FAST, which points to the current FAST system being highly capable of carrying out observations of IPS.

show abstract

Observations of interplanetary scintillation with a single-station mode at Urumqi

Cited by 7 publications

References 13 publications

Three-Dimensional Evolution of Solar Wind During Solar Cycles 22–24

Three-Dimensional Evolution of Solar Wind During Solar Cycles 22–24

Commission 49: Interplanetary Plasma and Heliosphere

A Pilot Study of Interplanetary Scintillation with FAST

Contact Info

Product

Resources

About