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.

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

2018 ◽  
Vol 4 (3) ◽  
pp. 33-38
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. 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 antenna overall 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.

scholarly journals Interferometric observation of Cygnus-А discrete radiosource scintillations at Irkutsk Incoherent Scatter radar

2016 ◽  
Vol 2 (1) ◽  
pp. 24-31
Author(s):  
Мария Глоба ◽  
Mariia Globa ◽  
Роман Васильев ◽  
Roman Vasilyev ◽  
Дмитрий Кушнарев ◽  
...  
Keyword(s):  
Angular Size ◽  
Brightness Distribution ◽  
Radiowave Propagation ◽  
Statistical Characteristics ◽  
Incoherent Scatter Radar ◽  
Incoherent Scatter ◽  
Cygnus A ◽  
Scatter Radar ◽  
Recording Channels ◽  
Interferometric Observation

We propose a new method for analysis of data from Irkutsk Incoherent Scatter Radar. The method allows us to accomplish interferometric observation of discrete cosmic radiosource characteristics. In this study, we analyzed ionospheric scintillations of the radio source Cygnus-A. Observations were made in 2013 during regular radar sessions within 5–15 days for different seasons, and the effective time of observation was 15–30 minutes per day. For interferometric analysis, the properties of correlation (coherence) coefficient of two independent recording channels were used. The statistical analysis of data from independent channels allows us to construct two-dimensional histograms of radiosource brightness distribution with period of 18 s and to determine parameters (the maximum position and the histogram width) representing position and angular size of radiosource for each histogram. It is shown that the change of statistical characteristics does not correlate with fluctuations in power (scintillations) of the signal caused by radiowave propagation through ionospheric irregularities.

scholarly journals Interferometric observation of Cygnus-А discrete radiosource scintillations at Irkutsk Incoherent Scatter radar

2016 ◽  
Vol 2 (1) ◽  
pp. 34-43
Author(s):  
Мария Глоба ◽  
Mariia Globa ◽  
Роман Васильев ◽  
Roman Vasilyev ◽  
Дмитрий Кушнарев ◽  
...  
Keyword(s):  
Radio Source ◽  
Angular Size ◽  
Brightness Distribution ◽  
Statistical Characteristics ◽  
Cosmic Radio ◽  
Incoherent Scatter Radar ◽  
Incoherent Scatter ◽  
Cygnus A ◽  
Scatter Radar ◽  
Interferometric Observation

We propose a new method for analyzing data from the Irkutsk Incoherent Scatter Radar. The method allows us to accomplish interferometric observation of discrete cosmic radio source characteristics. In this study, we analyze ionospheric scintillations of the radio source Cygnus-A. Observations were made in 2013 during regular radar sessions within 5–15 days for different seasons; the effective time of observation was 15–30 minutes per day. For interferometric analysis, the properties of correlation (coherence) coefficient of two independent recording channels were used. The statistical analysis of data from the independent channels allows us to construct two-dimensional histograms of radio source brightness distribution with a period of 18 s and to determine parameters (the maximum position and the histogram width) representing position and angular size of the radio source for each histogram. It is shown that the change of statistical characteristics does not correlate with fluctuations in power (scintillations) of the signal induced by radio wave propagation through ionospheric irregularities.

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.

Sign in / Sign up

Export Citation Format

Share Document