Aims. Simultaneous study of long quasi-periodic oscillations in sunspots (using line-of-sight magnetic field data) and nearby magnetic structures located above them (using radio emission data at 37 GHz) was the basic aim of this work. Methods. Data from the ground-based radio-telescope (Metsähovi Radio Observatory, Aalto University, Finland) and the Helioseismic and Magnetic Imager instrument on-board the Solar Dynamics Observatory spacecraft were obtained and analyzed. We used the wavelet (Morlet) analysis and the fast Fourier transform (FFT) method to obtain the oscillation periods. Results. Long-period oscillations in intervals of 200-400 min were found both in radio and in magnetic field data. The interpretation of these oscillations and their propagation to higher levels of the solar atmosphere are discussed in the context of a "shallow sunspot" model.

Aims. The investigation of long quasi-periodic oscillations in sunspots/active regions based on millimeter radio data was the main goal of this work. Methods. Data from simultaneous monitoring observations of solar active regions at 37 GHz and 93 GHz at two different groundbased radio telescopes were obtained. We analyzed them with the methods of wavelet (Morlet) and global wavelet spectrum analysis. Results. Two main ranges (10−60 and 80−130 min) of long quasi-periodic oscillations were found. We compared them with 17 GHz Nobeyama Radioheliograph (NoRH) data and obtained the same ranges for the long-period oscillations. The long-period oscillations found in this study are relatively stable and could be interpreted as a radial mode of sunspot oscillations.

The 5 July 2012 solar flare (11:39 -11:49 UT) with an increasing millimeter spectrum between 93 and 140 GHz is considered. We use space and ground-based observations in X-ray, extreme ultraviolet, microwave, and millimeter wave ranges obtained with the Reuven Ramaty High-Energy Solar Spectroscopic Imager, Solar Dynamics Observatory (SDO), Geostationary Operat ional E nvironmental Satellite, Radio Solar Telescope Network, and Bauman Moscow State Technical University millimeter radio telescope RT-7.5. The main parameters of thermal and accelerated electrons were determined through Xray spectral fitting assuming the homogeneous thermal source and thick-target model. From the data of the Atmospheric Imaging Assembly/SDO and differential emission measure calculations it is shown that the thermal coronal plasma gives a negligible contribution to the millimeter flare emission. Model calculations suggest that the observed increase of millimeter spectral flux with frequency is determined by gyrosynchrotron emission of high-energy ($\gtrsim 300$

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