scholarly journals LONG-TERM SOLAR FLUX OBSERVATIONS WITH IRKUTSK INCOHERENT SCATTER RADAR (IISR) IN 2011–2019

2020 ◽  
Vol 6 (3) ◽  
pp. 33-39
Author(s):  
Artem Setov ◽  
Dmitriy Kushnarev ◽  
Roman Vasilyev ◽  
Andrey Medvedev
Keyword(s):  
Radiation Pattern ◽  
High Sensitivity ◽  
Horn Antenna ◽  
Solar Flux ◽  
Incoherent Scatter Radar ◽  
Incoherent Scatter ◽  
Daily Average ◽  
Scatter Radar ◽  
Space Objects

Irkutsk incoherent scatter radar (IISR) is an oblongish horn antenna that operates in a meter waveband (154–162 MHz), has a 0.5°×20° beam, and a frequency steering allowing us to tilt the beam by 30° to the south. Besides active measurements of ionospheric conditions and monitoring of space objects, the radar is regularly used for passive radio astronomical observations. From May to August, the Sun crosses the radar field of view and can be in the maximum of the radiation pattern for about two hours. The known shape of the radiation pattern and the high sensitivity of the receiver allow us to conduct calibrated measurements of the solar flux in solar flux units during this period. We have developed a new approach to the calibration, which can be applied to all IISR archival passive data. In the paper, we present long-term observations (2011–2019) of the solar flux in May and summer. We describe the measurement method, present daily average values of the solar flux for this period of passive measurements, and compare it with the solar activity F10.7 index and solar flux measurements made at the Australian observatory Learmonth at 245 MHz. We show that the daily average flux for the period of observations at a frequency of ~161 MHz generally has values from 5 to 10 sfu.

scholarly journals LONG-TERM SOLAR FLUX OBSERVATIONS WITH IRKUTSK INCOHERENT SCATTER RADAR (IISR) IN 2011–2019

2020 ◽  
Vol 6 (3) ◽  
pp. 29-33
Author(s):  
Artem Setov ◽  
Dmitriy Kushnarev ◽  
Roman Vasilyev ◽  
Andrey Medvedev
Keyword(s):  
Radiation Pattern ◽  
High Sensitivity ◽  
Horn Antenna ◽  
Solar Flux ◽  
Incoherent Scatter Radar ◽  
Incoherent Scatter ◽  
Daily Average ◽  
Scatter Radar ◽  
Space Objects

Irkutsk incoherent scatter radar (IISR) is an oblongish horn antenna that operates in a meter waveband (154–162 MHz), has a 0.5°×20° beam, and a frequency steering allowing us to tilt the beam by 30° to the south. Besides active measurements of ionospheric conditions and monitoring of space objects, the radar is regularly used for passive radio astronomical observations. From May to August, the Sun crosses the radar field of view and can be in the maximum of the radiation pattern for about two hours. The known shape of the radiation pattern and the high sensitivity of the receiver allow us to conduct calibrated measurements of the solar flux in solar flux units during this period. We have developed a new approach to the calibration, which can be applied to all IISR archival passive data. In the paper, we present long-term observations (2011–2019) of the solar flux in May and summer. We describe the measurement method, present daily average values of the solar flux for this period of passive measurements, and compare it with the solar activity F10.7 index and solar flux measurements made at the Australian observatory Learmonth at 245 MHz. We show that the daily average flux for the period of observations at a frequency of ~161 MHz generally has values from 5 to 10 sfu.

scholarly journals Using incoherent scatter radar to investigate the neutral wind long-term trend over Arecibo

2011 ◽  
Vol 116 (A2) ◽  
pp. n/a-n/a ◽  
Author(s):  
P. T. Santos ◽  
C. G. M. Brum ◽  
C. A. Tepley ◽  
N. Aponte ◽  
S. A. González ◽  
...  
Keyword(s):  
Neutral Wind ◽  
Incoherent Scatter Radar ◽  
Term Trend ◽  
Incoherent Scatter ◽  
Scatter Radar ◽  
Long Term Trend

The speed of movement of piece space objects along the Earth's surface and its determination using incoherent scatter radar

2020 ◽  
Vol 1 (1) ◽  
pp. 56-75
Author(s):  
Valerii Pulyaev ◽  
Leonid Emelyanov ◽  
Artem Miroshnikov
Keyword(s):  
Space Debris ◽  
Vertical Component ◽  
High Energy ◽  
Optimal Placement ◽  
Incoherent Scatter Radar ◽  
Incoherent Scatter ◽  
Radar Beam ◽  
Scatter Radar ◽  
Space Objects ◽  
Coherent Reflection

Methodological features of registration and separation of coherent radar reflections from space objects and elements of “space debris” operating in orbit are considered. Registration occurs against the background of signals that are scattering of the probe radio wave on particles of the ionospheric plasma. Methods of how to obtain information about the components of the velocity vector of these objects in near-earth space with the help of specialized ground-based radar facilities are analyzed. Their disadvantage is the unreliable control of weak reflections from the elements of “space debris” if they have a small (up to centimeters) scattering cross section. The authors proposed to use the existing high-energy radar installations. Using the signals after the analog-to-digital conversion generated in quadrature, it is proposed to calculate the phase characteristics of the coherent reflection. The radial velocity of the objects along the radar beam is calculated by isolating the Doppler phase difference and statistically averaging these values ​​in the time of reflection. Similarly, by analyzing the time spent in the radar beam, the velocity component associated with the horizontal movement along the Earth’s surface is calculated. Real examples are given, when in one of the observation sessions on the reflection of a signal from a space object, the phase shift in each of its periods is calculated, and then, using the formula, proposed by the authors, the vertical component of the velocity of this object is calculated. Analyzing the observation time of this object in the beam of the transmitter antenna, an example of the calculation and the component of its horizontal velocity is shown. The block diagram of the radar used to calculate the specified parameters of the movement of space objects is presented. The developed approach is an effective solution of many practical problems in those industries that ensure the operation of spacecraft, ensuring the safety of space stations, optimal placement of objects in orbit, etc. Keywords: Incoherent scatter radar, space objects, coherent reflection, signal phase characteristics, radial and horizontal speed

scholarly journals Ionospheric climatology and variability from long-term and multiple incoherent scatter radar observations: variability

2008 ◽  
Vol 26 (6) ◽  
pp. 1525-1537 ◽  
Author(s):  
S.-R. Zhang ◽  
J. M. Holt
Keyword(s):  
Solar Activity ◽  
Electron Density ◽  
Geomagnetic Activity ◽  
Plasma Temperature ◽  
High Electron ◽  
High Electron Density ◽  
Incoherent Scatter Radar ◽  
Incoherent Scatter ◽  
Scatter Radar

Abstract. Long-term incoherent scatter radar (ISR) observations are used to study ionospheric variability for two midlatitude sites, Millstone Hill and St. Santin. This work is based on our prior efforts which resulted in an empirical model system, ISR Ionospheric Model (ISRIM), of climatology (and now variability) of the ionosphere. We assume that the variability can be expressed in three terms, the background, solar activity and geomagnetic activity components, each of which is a function of local time, season and height. So the background variability is ascribed mostly to the day-to-day variability arising from non solar and geomagnetic activity sources. (1) The background variability shows clear differences between the bottomside and the topside and changes with season. The Ne variability is low in the bottomside in summer, and high in the topside in winter and spring. The plasma temperature variability increases with height, and reaches a minimum in summer. Ti variability has a marked maximum in spring; at Millstone Hill it is twice as high as at St. Santin. (2) For enhanced solar activity conditions, the overall variability in Ne is reduced in the bottomside of the ionosphere and increases in the topside. For Te, the solar activity enhancement reduces the variability in seasons of high electron density (winter and equinox) at altitudes of high electron density (near the F2-peak). For Ti, however, while the variability tends to decrease at Millstone Hill (except for altitudes near 200 km), it increases at St. Santin for altitudes up to 350 km; the solar flux influence on the variability tends to be stronger at St. Santin than at Millstone Hill.

scholarly journals First results of absolute measurements of solar flux at the Irkutsk Incoherent Scatter Radar (IISR)

2018 ◽  
Vol 4 (3) ◽  
pp. 24-27 ◽  
Author(s):  
Артём Сетов ◽  
Artem Setov ◽  
Мария Глоба ◽  
Mariia Globa ◽  
Андрей Медведев ◽  
...  
Keyword(s):  
Flux Density ◽  
Solar Flux ◽  
Radio Sources ◽  
Frequency Range ◽  
Incoherent Scatter Radar ◽  
Incoherent Scatter ◽  
Cygnus A ◽  
Scatter Radar ◽  
Absolute Measurements ◽  
Operation Frequency

The Irkutsk Incoherent Scatter Radar (IISR) allows us to carry out passive radio observations of the Sun and other powerful radio sources. We describe a method for absolute measurements of spectral flux density of solar radiation at IISR. The absolute measurements are meant to determine the flux density in physical units [W·m–2·Hz–1]. The IISR antenna is a horn with frequency beam steering, therefore radio sources can be observed at different frequencies. Also there is a polarization filter in the antenna aperture, which passes only single (horizontal) polarization. To acquire flux density absolute values, the IISR receiver is calibrated by the Cygnus-A radiation. Since the Sun’s position in the IISR antenna pattern is determined by a frequency differing from the Cygnus-A observation frequency, we perform an additional calibration of the frequency response in the 154–162 MHz operation frequency range, using the background sky noise. The solar disk size is comparable with the main beam width in the north—south direction, hence the need to take into account the shape of the brightness distribution in the operation frequency range. The average flux density of the quiet-Sun radiation was ~5 sfu (solar flux units, 10–22 W·m–2·Hz–1) at the 161 MHz frequency.

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