Amplitude modulated drift wave packets in a nonuniform magnetoplasma

TL;DR

This paper studies how low-frequency drift wave packets in a nonuniform magnetoplasma are affected by amplitude modulation, revealing conditions for stability and the formation of solitons using a nonlinear Schrödinger equation.

Contribution

It introduces a nonlinear Schrödinger equation framework to analyze amplitude modulation and stability of drift wave packets in nonuniform magnetoplasmas, highlighting new stability criteria.

Findings

Drift wave packets are stable for wave numbers 0<k<1/√2.

Unstable for wave numbers 1/√2<k<1.

Possibility of bright and dark envelope solitons.

Abstract

We consider the amplitude modulation of low-frequency, long wavelength electrostatic drift wave packets in a nonuniform magnetoplasma with the effects of equilibrium density, electron temperature and magnetic field inhomogeneities. The dynamics of the modulated drift wave packet is governed by a nonlinear Schr\"odinger equation. The latter is used to study the modulational instability of a Stoke's wave train to a small longitudinal perturbation. It is shown that the drift wave packet is stable (unstable) against the modulation when the drift wave number lies in $0< k < 1/\sqrt{2}$ $(1/\sqrt{2}<k<1)$. Thus, the modulated drift wave packet can propagate in the form of bright and dark envelope solitons or as a drift wave rogon.