QUASI-PERIODIC OSCILLATIONS FROM STELLAR FLARES AND DIAGNOSTICS OF FLARING PLASMA

Quasi-periodic oscillations in radio, X-rays, and optical emission from flaring stars are studied using the coronal seismology method. Two approaches are used: the first considers stellar coronal magnetic loops as resonators for MHD-oscillations, the second suggests that a coronal loop is an equivalent electric (RLC) circuit. It is shown that both approaches provide good diagnostic tools for parameters of flares on the Sun and late-type stars. A possible origin of high-frequency QPO from Soft Gamma Ray Repeaters is proposed.