Model of vortex tubes in the low-latitude plasma sheet of the earth magnetosphere Original Research Article

Theoretical model is proposed to explain specific features of compressional waves of the Pc 4–5 frequency range which were observed with the INTERBALL-1 probe in the middle tail of the Earth magnetosphere. The waves exhibit anti-phase disturbances in thermal plasma and magnetic field pressures. Large-scale vortical plasma motions are associated with the waves. Coupling of the drift Alfven and magnetosonic waves is considered with inclusion of finite plasma compressibility and disturbances along the local magnetic field line. In limiting cases derived equations are reduced to well-known Kadomtsev-Pogutse and Hasegawa-Mima equations. Partial solutions take form of vortices. According to proposed model, two-dimensional vortical motion of a plasma transversely to the local field line is accompanied by nonlinear magnetosonic waves propagating in flux tubes almost along the field lines.