The article discusses characteristics, fundamental and applied tasks of the Siberian Radioheliograph that is developed at the ISTP SB RAS Radio Astrophysical Observatory and spectropolarimetric complex that measures the total flux of solar radio emission. The multi-wave mapping of the Sun in the microwave range is a powerful and relatively inexpensive, in comparison with space technologies, means of observing solar activity processes and diagnosing plasma parameters. All-weather monitoring of electromagnetic solar emission (in the range from meter to millimeter waves, including measurements of the solar activity index at 2.8 GHz), and at the location of other diverse diagnostic facilities of the Heliogeophysical Complex, is of particular value. Radioheliograph data is necessary to develop and implement methods of short-term forecast of solar flares, measurements of kinematics and characteristics of coronal mass ejection plasma, forecast of characteristics of fast solar wind streams.

We describe methods for monitoring eruption activity with the first phase of the multiwave Siberian Radioheliograph (SRH-48). We give examples of the recorded eruptive events: 1) rise of a prominence above the limb observed in the radio map sequence of April 24, 2017; 2) a jet recorded on August 2, 2017, whose cold matter screened a compact microwave source for several tens of minutes. The shading due to the jet appearance was observed on SRH-48 correlation curves as the so-called "negative" burst. Using the "negative" burst on the correlation curves of February 9, 2017 as an example, we show that the intervals with depression of the microwave emission of local sources are not always caused by shading of their emission. In this event, the radio brightness decreased within ten hour period of the increased quasi-stationary emission during the development of AR 12635 magnetic structure. Similar behavior was observed in EUV, SXR, and radio emission at 17 GHz.

The goal of this work is to study the atmospheric heating above isolated AR 12635 during a period in which a quasistationary increase in microwave and soft X-ray emission is combined with a series of B- and C-class microflares. Analysis of photospheric vector magnetograms showed that an increase in the SXR brightness lasting 14 hours was observed during the simplification of the magnetic structure and the growth of vertical currents in the head part of the active region. A long-term increase of SXR and microwave emission occurred when the total unsigned vertical current exceeded the critical value and coincided in time with the increased level of the emission measure calculated from the GOES X-ray data. Against the background of quasistationary emission, microflares lasting 6–10 minutes occurred. In the hard X-ray range, bursts are recorded with RHESSI channels up to 25 keV. In microwave emission, pulsed and smooth components are distinguished during microflares. The first component was recorded in the 4.5–7.5 GHz range at the beginning of microflares and it is generated by a small population of relativistic electrons by the gyrosychrotron mechanism. The smooth component of the bursts dominated at 17 GHz and was emitted by bremsstrahlung. It is shown that the sources of quasistationary emission and microflares coincide with each other and with the bremsstrahlung source calculated from the differential emission measure obtained from the EUV maps. Coronal magnetic field reconstruction shows that the release of energy on both timescales occurs in a stably existing bundle of magnetic field lines.

We discuss the method for automatic calibration of solar radio images derived from the first stage of the multiwave Siberian Radioheliograph (SRH-48). SRH is a 48-element T-shaped radiointerferometer in the 4–8 GHz frequency range. Since the end of 2017, the number of frequencies has been increased to 32. The method is implemented in Python programming language. We give examples of calibration for SRH instrument values in brightness temperature of the quiet and active Sun at several frequencies for four eruptive events: June 19, 2017, July 25, 2016, April 24, 2017, and April 19, 2017. In conclusion, we present spectra for three events, as well as brightness temperature estimates by flux, angular size of filaments, and emission measure.

The article discusses characteristics, fundamental and applied tasks of the Siberian Radioheliograph that is developed at the ISTP SB RAS Radio Astrophysical Observatory and spectropolarimetric complex that measures the total flux of solar radio emission. The multi-wave mapping of the Sun in the microwave range is a powerful and relatively inexpensive, in comparison with space technologies, means of observing solar activity processes and diagnosing plasma parameters. All-weather monitoring of electromagnetic solar emission (in the range from meter to millimeter waves, including measurements of the solar activity index at 2.8 GHz), and at the location of other diverse diagnostic facilities of the Heliogeophysical Complex, is of particular value. Radioheliograph data is necessary to develop and implement methods of short-term forecast of solar flares, measurements of kinematics and characteristics of coronal mass ejection plasma, forecast of characteristics of fast solar wind streams.