Modulational Instability in the Interaction of Fast and Slow Magnetosonic Modes

Abstract

The present paper studies the magnetic filaments produced by the interaction between the high-frequency magnetosonic wave and low-frequency magnetosonic wave. These phenomena can be explained by using an envelope solitary wave solution of the nonlinear Schrodinger equation (NLSE). The analytical results from NLSE are in agreement with the numerical result from Ref. Modi et al. (Phys. Plasmas 21: 102305, 2014). Both the linear and the nonlinear modulational instability are studied for the system. Two critical points are obtained. The first critical point gives the regions of both the instability and the stability, while the second one shows that if the perturbed wave number is close to the second critical point, the perturbed wave may be the most stable one. It is also found that all the higher order perturbed waves can be neglected in the stability region when the perturbed wave number is larger than that of the first critical point.