The solitonic, periodic and quasiperiodic solutions that obey the full system
of transport equations describing one-dimensional motion of a isotropic collisionless
quasineutral plasma in a magnetic field are treated. The domains of physical parameters
of such a plasma are determined for fast and slow magnetoacoustic
branches, where solitary waves and generalized solitary waves exist. In the parameter
domain where solitary waves are replaced by non-local generalized solitary
waves, the localized disturbances are subject to decay, which has qualitatively different
mechanisms for fast and slow magnetoacoustic waves. The specific feature of
the decay process for fast waves is found to be characterized by a decrease of energy
of the disturbance due to quasistationary radiation of a resonant periodic wave
of the same nature. Analogous disturbances, having the form of a slow magnetoacoustic
solitary wave core, practically do not radiate resonant Alfvénic modes, but
rapidly lose energy as a result of continuous shedding of a slow-wave component.
Various types of shock waves are also considered. Their structure is formed by existing
solitonic configurations – solitary and generalized solitary waves. Possibilities
of observations of solitary waves and their decay in a real plasma are discussed.