Solar flares and coronal mass ejections (CME) are the most powerful manifestations of solar activity. Both phenomena associated with the evolution of the spatial structure of the magnetic field of active regions (AR). It is known that not all powerful flares accompanied by CME. In some cases, CME are observed, associated with very low intensity bursts. At the same time, the observational signs that determine the ability of AR to cause the eruption of matter from AR into the high layers of the solar corona are still not clear. This makes it difficult to understand the physical mechanism of eruption initiation (CME trigger). The purpose of this work is to search for observational signs of the onset of the eruptive process. For this, we conducted a comparative analysis of pre-flare and flare conditions for 6 flare events, accompanied by CME, and 5 events not accompanied by CME.

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Spatiotemporal butterfly diagram of Greenwich sunspot area record demonstrates major features of 11-year activity cycle. Here we translate sunspot areas into magnetic flux with known empirical relation and measure the distances between wings in butterfly diagram as between two-dimensional statistical distributions. We found that spatiotemporal structure of butterfly wings is closer for a series of stronger cycles whereas analog of Gnevyshev-Ohl rule is completed for a series of smaller cycles with closer distances in even-odd cycles.

We present a study of quasi-periodic oscillations (QPOs) of microwave emission from some solar active regions (ARs) on pre-flare phase. We used the Nobeyama Radioheliograph (NoRH) daily observations. The radio maps of the whole solar disk were synthesized in nonstandard mode with a cadence of ten seconds and ten seconds averaging. We computed the time series of maximum brightness temperature and total flux over selected field-of-view (FOV) and used spectral wavelet analysis of the time series. We found that in most of the cases an increase in the power of QPOs before flares is observed. The periods of oscillation are different and vary from 3 to 100 minutes. The duration of pre-flare wavetrains in periods of oscillations is approximately the same for all cases and is about 5 pulses. The effect of the occurrence of the QPOs before flares can be interpreted as a relationship between MHD waves propagating along the magnetic flux tube of sunspot and beginning of the flares and can be considered as a flare precursor.

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