Long-lived Microbursts in Decimetric Wavelength Range

L.V. Yasnov1, V.M. Bogod2, A.G. Stupishin2

1Research Institute of Radiophysics, St.Petersburg State University, Russia
2Special Astrophysical Observatory, Russian Academy of Sciences, Russia

For the first time statistical research for long-living microbursts () at decimetric wavelengths which were observed on the one-dimensional scans by the RATAN-600 radiotelescope in intensity and circular polarization with a sensitivity of about 5-10 Jy is carried out . The flux of microbursts is in the range 0.001-0.1 s.f.u., the degree of polarization is from 10% up to 100%, the duration of individual impulses - about 1-2 seconds. The microbursts and background sources exist for several days and appear at sites of prolonged energy release. Comparison of (); with noise storms at meter range of wavelengths (NS) is executed. Such analysis shows a high probability that (); are manifestation of NS at decimeter range of wavelengths. The possible reason of essential distinction of radio emission fluxes between (); and NS is analysed. Within the limits of common model of generation of radiowaves for (); and NS ! is shown that unlike type bursts I type (); are connected with noncoherent mechanism of generation of Langmuir waves. Radiation of (); is closer to continual radiation of NS, but because of high rate of pitch-angular diffusion it has a pulse character.