High-Quality Fast QPOs from Magnetars: an Electric Circuit Model

An interpretation of high-frequency (20-2400 Hz) fast quasi-periodic oscillations of magnetars in terms of an equivalent electric circuit is given. Observed periods and the very high quality of quasi-periodic oscillations are explained. The oscillation source is represented as a hot electron-positron plasma in a 'trapped fireball', a system of current-carrying magnetic loops of various sizes. The physical parameters of a 'trapped fireball' in the flare of SGR, 1806-20 (2004 December 27) are estimated.