Published online by Cambridge University Press: 13 March 2009
The filamentation and collapse of Langmuir waves in a weak magnetic field are analysed in two particular cases of low-frequency acoustic perturbations: (i) adiabatic perturbations which correspond to subsonic collapse, and (ii) nonadiabatic perturbations which correspond to supersonic collapse. Here the existence of Langmuir filaments and Langmuir collapse in a weak magnetic field are due to nonlinear interaction of high-frequency Langmuir waves (which make small angle with the external magnetic field) with low-frequency acoustic perturbations along the magnetic field.