Statistical Study of Microwave Pulsations During Flares in Single Loops

E.G. Kupriyanova$^1$, V.F. Melnikov$^2$, K. Shibasaki$^3$

$^1$Pulkovo Astronomical Observatory, Russian Academy of Sciences, St.-Petersburg 196140, Russia
$^2$ Radiophysical Research Institute (NIRFI), Nizhny Novgorod, 603950, Russia
$^3$Nobeyama Radio Observatory, National Astronomical Observatory of Japan, Minamimaki, Minamisaku, Nagano 384-1305, Japan

One of the most important tools for studying non-stationary processes in solar flaring loops is the analysis of pulsations and oscillations of their radio emission with characteristic MHD time scales. The pulsations can be caused by oscillations of the energy release and particle acceleration process or by MHD oscillations of the magnetic loop containing accelerated electrons and subsequent modulation of their radio emission. Observations with high temporal and spatial resolution using Nobeyama Radioheliograph and Radio Polarimeters give a possibility to study such pulsation processes in flaring loops. In this work we study microwave pulsations observed in 12 flaring events with well resolved single microwave flaring loops. For the study we use methods of both Fourier and wavelet spectral analysis to derive amplitude and phase characteristics of the quasi-periodical pulsations.