ULF waves at Mercury: Earth, the giants, and their little brother compared Original Research Article

ULF pulsations are magnetohydrodynamic waves in the terrestrial magnetosphere. They are generated by solar wind buffeting of the magnetosphere, Kelvin–Helmholtz instability of the magnetopause, or particle–wave interactions within the magnetospheric plasma. As a major damping mechanism the terrestrial ionosphere has been identified. Wave modes and wave propagation in the inhomogeneous magnetosphere is described in terms of global toroidal and poloidal oscillations or phenomena such as the field line resonance. An attempt is made to compare ULF pulsations with other comparable wave observations in the magnetospheres of Mercury, Jupiter, and Saturn. Special emphasize is paid to low frequency waves in the Hermean magnetosphere as this global system can not be described as a magnetohydrodynamic plasma which alters physical concepts useful in the terrestrial magnetosphere.