  For a system of equations describing one-dimensional nonlinear oscillations
in a magnetoactive plasma, we study the effect of a constant magnetic field on
the breaking of oscillations. For the nonrelativistic case, a criterion for the
formation of a finite-dimensional singularity is obtained in terms of the
initial data. It is shown that the enhancement of the magnetic field basically
leads to an expansion of the class of initial data providing the global
smoothness of the solution. The nature of the singularities of the solutions is
illustrated by numerical examples.
