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

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

Prospective IS-MST radar. Potential and diagnostic capabilities

In the next few years, a new radar is planned to be built near Irkutsk. It should have capabilities of incoherent scatter (IS) radars and mesosphere-stratosphere-troposphere (MST) radars [Zherebtsov et al., 2011]. The IS-MST radar is a phased array of two separated antenna panels with a multichannel digital receiving system, which allows detailed space-time processing of backscattered signal. This paper describes characteristics, configuration, and capabilities of the antenna and transceiver systems of this radar. We estimate its potential in basic operating modes to study the ionosphere by the IS method at heights above 100 km and the atmosphere with the use of signals scattered from refractive index fluctuations, caused by turbulent mixing at heights below 100 km. The modeling shows that the radar will allow us to regularly measure neutral atmosphere parameters at heights up to 26 km as well as to observe mesosphere summer echoes at heights near 85 km in the presence of charged ice particles (an increase in Schmidt number) and mesosphere winter echoes at heights near 65 km with increasing background electron density. Evaluation of radar resources at the IS mode in two height ranges 100–600 and 600–2000 km demonstrates that in the daytime and with the accumulation time of 10 min, the upper boundaries of electron density and ionospheric plasma temperature are ~1500 and ~1300 km respectively, with the standard deviation of no more than 10 %. The upper boundary of plasma drift velocity is ~1100 km with the standard deviation of 45 m/s. The estimation of interferometric capabilities of the MST radar shows that it has a high sensitivity to objects of angular size near 7.5 arc min, and its potential accuracy in determining target angles can reach 40 arc sec

Modern heating facility for research into the mid-latitude ionosphere

© Meandros Medical and Dental Journal. The development of new devices for research in physics of the upper atmosphere and near-Earth space, which can be used to carry out controlled experiments on the modification of the ionosphere by powerful short-wave radiation, is an urgent task of modern solar-terrestrial physics, space weather, operation of satellite constellations in near-Earth space, radio communications, and radar. The paper describes a modern heating facility, created within the framework of the National Heliogeophysical Complex of the Russian Academy of Sciences. We review the tasks facing the heater, discuss its main technical characteristics, and describe the capability of the observational infrastructure surrounding the heating facility. The paper justifies the long-term benefits of the development of a heating facility at middle latitudes of Eastern Siberia, which can radiate in a frequency range 2.5-6.0 MHz with an effective power of the order of several hundred megawatts. It is important that the heater will be surrounded by such multifunctional instruments as the modern incoherent scatter radar, mesostratospheric lidar, observational systems that can provide a wide range of possibilities for diagnosing artificial plasma disturbances and artificial airglow structures

RADIOPHYSICAL CLUSTER OF INSTRUMENTS OF THE NATIONAL HELIOGEOPHYSICAL COMPLEX OF RAS: TASKS AND CURRENT STATE

12-19В работе представлен обзор текущего состояния проекта кластера радиофизических инструментов Национального гелиогеофизического комплекса Российской академии наук, предназначенных для изучения верхней атмосферы и ионосферы Земли. Рассмотрены технические особенности реализации высокопотенциального радара метрового диапазона, сети когерентных радаров декаметрового диапазона и среднеширотного нагревного стенда.The paper presents an overview of the current state of the project of the radiophysical instrument cluster of the National heliogeophysical complex of the Russian Academy of Sciences, designed to study the upper atmosphere and ionosphere of the Earth. Technical features of implementation of high-potential radar of meter radiorange, network of coherent radars of decameter radiorange and mid-latitude heating facility are considered

RADIOPHYSICAL CLUSTER OF INSTRUMENTS OF THE NATIONAL HELIOGEOPHYSICAL COMPLEX OF RAS: TASKS AND CURRENT STATE

В работе представлен обзор текущего состояния проекта кластера радиофизических инструментов Национального гелиогеофизического комплекса Российской академии наук, предназначенных для изучения верхней атмосферы и ионосферы Земли. Рассмотрены технические особенности реализации высокопотенциального радара метрового диапазона, сети когерентных радаров декаметрового диапазона и среднеширотного нагревного стенда.The paper presents an overview of the current state of the project of the radiophysical instrument cluster of the National heliogeophysical complex of the Russian Academy of Sciences, designed to study the upper atmosphere and ionosphere of the Earth. Technical features of implementation of high-potential radar of meter radiorange, network of coherent radars of decameter radiorange and mid-latitude heating facility are considered.12-1