RESPONSE OF ENERGETIC PARTICLES TO MAGNETOSPHERIC ULTRA-LOW-FREQUENCY WAVES

Ultra-low-frequency (ULF) waves in the space physics context are the lowest-frequency plasma waves propagating in the Earth's magnetosphere. Although the propagation of the waves is explained in magnetohydrodynamic (MHD) theory, excitation of the waves involves not only MHD but also kinetic process. In this article, we describe how in situ magnetic field and particle measurements can be used to distinguish the basic properties of ULF waves, including the azimuthal wave number of the standing wave structure and the propagation direction. Examples are taken from observations with the AMPTE/CCE spacecraft.