, V.E. Abramov-Maximov, K. Shibasaki
G.B. Gelfreikh, V.E. Abramov-Maximov, K. Shibasaki
Pulkovo Astronomical Observatory, Russian Academy of Sciences,
St.-Petersburg 196140, Russia
Nobeyama Radio Observatory, National Astronomical Observatory of Japan,
Minamimaki, Minamisaku, Nagano 384-1305, Japan
Microwave observations with two dimensional spatial resolution at the wavelength 1.76 cm have open an effective way to study MHD waves propagation and plasma structures in the solar atmosphere, lower corona including. The most effective analysis was found from observations of quasi periodic oscillations (QPOs) of sunspot-associated sources. They include both 3-minute and 5-minute oscillations well known from the optical studies. In this case, however, the radiation is generated in CCTR, giving essentially new information. Besides the QPOs with periods of dozens of minutes are observed generated probably mostly by coronal loop structures. The periods of hours are also registered and their nature, partially referred to the global solar activity is still needs further more detailed analysis. On the other hand, the modern understanding of the processes resulting in the eruption of energy in the solar flares and CME are the results of energy accumulation in the corona or chromosphere produced by some reconstruction of the plasma structures and we are still far from the satisfactory observational interpretation of the above processes. The QPO of the solar ARs were found decades ago and their connections with the flare activity was registered. Nevertheless the physical nature and possible forecasting applications are still far from reasonable level of knowledge. New development of microwave instruments with high spatial resolution and regular observations, especially Nobeyama Radioheliograph opened a new era in such studies. In this presentation we present results of investigations of parameters of oscillations a number for ARs with different level of flare activity and also variations of these due to flare activity of the regions. Such an analysis may lead to better understanding of the physics of the accumulation and release of the energy of the flares and CMEs. Results of such studies presented in this report, are based on an analyses of the Nobeyama radio maps of the sun with the 10 sec averaging and covering periods of hours of observations. Comparing these observations with spectral parameters of the active regions obtained with the RATAN-600 was also essential part of the study and the interpretations. This study was partially supported by the Program of the Presidium or the Russian Academy of Sciences.