抄録
Perpendicular stability of the one-dimensional propagation of coupled Langmuir and ion-acoustic solitary waves against perturbations varying slowly in both space and time is investigated theoretically. The system is assumed to be isotropic and describable by the collisionless two-fluid equations with zero ion temperature. Both near-sonic and subsonic solitary waves are considered and the perturbations are assumed to be represented in terms of the amplitude and velocity perturbations of the solitary waves. It is found that except for the case of vanishing propagation speed, the amplitude perturbation grows initially but damps asymptotically for long times, whereas the velocity perturbation always damps with time. The time evolution of the perturbations is scaled by their wavenumber, and the maximum amplification factor increases with the solitary wave amplitude.
