S. G. Tagare

Nonlinear propagation of ion-cyclotron modes

It is shown that the nonlinear interaction of large amplitude electrostatic ion‐cyclotron oscillations with low‐frequency perturbations causes a modulational instability. The most important cases of adiabatic density perturbations and low‐frequency changes in the magnetic field strength are considered. The nonlinear equation which governs the asymptotic state of the modulationally unstable ion‐cyclotron mode admits a soliton or soliton‐like solution for the electric potential.

Existence and propagation of finite amplitude upper hybrid solitary waves

Known results on the coupling of upper hybrid waves with linear low-frequency background modulations are generalised to include finite amplitude density and magnetic field modulations. The present results are thus valid beyond the usual cubic nonlinear Schrodinger equation description. Conditions for the existence of envelope solitons are derived. Super- and sub-Alfvenic upper hybrid solitons with their associated density depressions or humps can appear. Special cases are discussed.

Nonlinear cylindrical ion‐acoustic waves in a warm collisional plasma

The propagation of a nonlinear cylindrical ion‐acoustic wave in a collisional plasma is shown to be governed by the modified Korteweg–de Vries–Burgers equation. The stationary shock solution valid at early times is presented.

Effect of magnetic field on propagation of nonlinear ion-acoustic wave

The Korteweg–de Vries equations describing the propagation of slow and fast nonlinear ion‐acoustic waves in a magnetic field are derived by using a perturbation method. The effect of the direction of propagation on the amplitude and width of the solitary solutions are discussed.

Stimulated ion surface waves on a semi-infinite plasma

It is shown that high-frequency volume plasma waves can stimulate the excitation of ion surface waves due to the parametric interaction. Explicit results for the growth rate and the threshold of the instability are obtained.

Filamentation of lower-hybrid turbulence by adiabatic perturbations in a magnetized plasma

Abstract It is shown that stationary turbulence consisting of an ensemble of small amplitude lower hybrid wave packets becomes unstable against adiabatic perturbations along the external magnetic field. The growth rate and the threshold of the instability are calculated.

Evolution of finite amplitude whistler wave

The coupling of a large amplitude electron whistler wave with ion density perturbations is considered. It is shown that this coupling leads to the formation of supersonic whistler solitons. The properties and existence criteria of the latter are discussed in detail.

Propagation of fast ion-acoustic waves in multi-dimensions

Abstract By using a perturbation method, it is shown that the nonlinear fast ion-acoustic wave of a small but finite amplitude in a collisionless plasma consisting of hot and isothermal electrons and cold ions is governed by a nonlinear equation in which, in general, the coefficients of nonlinear and dispersive terms are not constant but depend on the form of the wave-front and the lowest order term contains mean curvature of the wave-front as its coefficient.

Kinetic Modulational Instability of Upper-hybrid Turbulence

Abstract It is shown that a plasma containing randomly distributed non-interacting upper-hybrid waves can become unstable against ion quasi-modes. The growth rate of the instability is presented.

Solitary Filaments of Coupled Electromagnetic Wave and Finite Amplitude Ion Fluctuations

Abstract We show analytically that the nonlinear coupling of a large amplitude electromagnetic wave with finite amplitude ion fluctuations leads to filamentation. The latter consists of striations of the electromagnetic radiation trapped in depressions of the plasma density. The filamentation is found to be either standing or moving normal to the direction of the incoming radiation. Criteria for the existence of localized filaments are obtained. Small amplitude results are discussed.