G. Murtaza

Nonlinear generation of electromagnetic waves in a magnetoplasma

Une onde hybride inferieure damplitude finie peut se decomposer en une onde cyclotron ionique/hybride inferieure electrostatique se propageant perpendiculairement et une onde electromagnetique a polarisation circulaire gauche ou un rayonnement de mode ordinaire. Relations de dispersion non lineaires et taux de croissance

Generation of extraordinary mode radiation by an electrostatic pump

It is shown that an electrostatic wave near the upper‐hybrid resonance frequency can parametrically excite extraordinary (X‐) mode radiation accompanied by a great variety of low‐frequency oscillations. The latter may include the lower‐hybrid, the electron‐acoustic, the ion‐cyclotron, and the shear Alfven waves. Nonlinear dispersion relations and the growth rates are obtained for each case. Comparison of our investigation to an earlier work and its possible application to space plasmas are pointed out.

Finite Larmor radius effects on Alfvén radiative thermal instability

It is shown that finite gyroradius effects can couple the shear Alfven waves to the radiative thermal mode to produce an Alfven condensation instability.

Decay of a whistler

Abstract It is shown that a finite amplitude whistler can nonlinearly excite lower-hybrid and short wavelength ion-cyclotron waves. The growth rate and threshold are obtained. Application of our investigation to space plasmas is pointed out.

Nonlinear destabilization of tearing modes

It is shown that a spectrum of stationary electrostatic fluctuations can destabilize the tearing modes. Since the growth of this nonlinear instability is rapid, it can affect the plasma confinement in magnetic fusion devices.

New electron-temperature-gradient drift wave instabilities and anomalous thermal transport in magnetized electron plasmas

New electron‐temperature‐gradient‐driven electrostatic drift wave instabilities are shown to arise in magnetized electron plasmas. The quasilinear electron energy transport caused by such nonthermal drift waves is also obtained.

Nonlinear magnetic electron drift waves in magnetized plasmas

Derivation des equations non lineaires gouvernant levolution espace-temps des ondes de derive electroniques dans un magnetoplasma inhomogene. Le gradient de pression electronique a lequilibre est maintenu par le gradient du champ magnetique externe. Une instabilite oscillatoire se produit. Etude des tourbillons de derive magnetique et de la limitation de la vitesse des tourbillons due au champ magnetique externe

Radiative condensation instability in an inhomogeneous magnetized plasma

A general dispersion relation for the radiative condensation instability in an inhomogeneous magnetized plasma is derived from the modified Braginskii two-fluid equations including radiative heat loss effects. It is found that for parameter values relevant to the marfe regions of current Tokamaks the radiative thermal instability can be linearly coupled to the ion acoustic and drift waves. The dispersion relations and instability characteristics of the coupled modes are presented.

Nonlinear drift-tearing mode instability in the presence of electrostatic microturbulence

The nonlinear interaction of drift-tearing modes in the presence of an electrostatic drift wave turbulence background is investigated. The authors assume that the interaction is significant only when the magnetic islands of the modes overlap sufficiently. It is found that there exist fast growing nonlinear instabilities driven by an effective (turbulent) electron viscosity, which may be orders of magnitude larger than the fluid viscosity.

Drift-ballooning modes in the presence of charged dust impurities in a nonuniform rotating magnetoplasma

The linear and nonlinear properties of drift-ballooning modes in the presence of an equilibrium electric field and stationary charged dust grains are examined. It is found that the presence of these two contribute to the stability of the ballooning mode. Furthermore, the nonlinear coupling between finite amplitude drift-ballooning modes gives rise to different types of coherent vortex structures, which can affect the transport properties of an inhomogeneous magnetized plasma. The relevance of the investigation to laboratory and astrophysical plasmas is discussed.